Both yellow birch and sweet birch have nearly identical leaf shape and both give an odor of wintergreen when crushed. Seedlings of the two species can be very hard to tell apart. To differentiate the two, the range, buds, or bark must be examined. The ranges do overlap in Appalachia where they commonly grow together, but sweet birch does not grow west of Ohio or north into Canada whereas yellow birch does. Sweet birch also has black non-peeling bark compared to the lighter, bronze colored, peeling bark of yellow birch. For young trees where bark has not yet developed, yellow birch can also be identified by its hairy buds and stems; sweet birch has hairless buds.


The yellow birch was first described by François André Michaux in 1812 as Betula lutea. In 1904, Nathaniel Lord Britton described what he considered to be a new closely related species of birch as Betula alleghaniensis, differing from B. lutea by its shorter fruiting scales and mostly cordate (vs. rarely cordate) leaf bases. After comparing the descriptions and illustrations of B. lutea and B. alleghaniensis, Merritt Fernald found the latter to be identical to B. lutea, but did confirm the existence of two varieties. Later, the name Betula lutea was determined illegitimate as it was superfluous to the older name that Michaux had listed as a synonym, Betula excelsa Aiton (1789). Additionally, the type specimen of Betula excelsa was found not to be a yellow birch, making Betula alleghaniensis the oldest and correct replacement name for the illegitimate B. lutea.
The specific epithet alleghaniensis means "of the Allegheny Mountains". In addition to "yellow" or "golden" birch, B. alleghaniensis has also been called gray birch, silver birch, tall birch, and swamp birch, though it shares several of these names with other Betula species.


Several varieties have been named, but are not recognized as distinct by modern authors:
B. a. var. alleghaniensis — scales on the fruiting catkins 5–8 mm
B. a. var. macrolepis (Fernald) Brayshaw — scales on the fruiting catkins which measure 8–13 mm
B. a. var. fallax (Fassett) Brayshaw — dark brown bark that typically does not exfoliate into shreds or curly flakes at the surface, especially noticeable when the bark is wet


It hybridizes with Betula pumila to form Betula × purpusii in larch swamps. These hybrids are rather common and shrubby in growth pattern and may have an odor of wintergreen or rusty-hairy twigs. The leaf shape is intermediate between both species.
It can also hybridize with Betula papyrifera in northern regions where their ranges overlap. It has seldom been reported but is thought to be more common than realized. In most features it is intermediate between the two parents.


Its native range extends from Newfoundland to Prince Edward Island, Nova Scotia, New Brunswick, southern Quebec and Ontario, and the southeast corner of Manitoba in Canada, west to Minnesota, and south in the Appalachian Mountains to northern Georgia. While its range extends as far south as Georgia, it is most abundant in the northern part of its range. In southern Pennsylvania, it is rare and generally only found along bodies of water in cool, mature woods, and it only occurs at high elevations from Maryland southward. It grows in USDA zones 3-7.
B. alleghaniensis prefers to grow in cooler conditions and is often found on north facing slopes, swamps, stream banks, and rich woods. It does not grow well in dry regions or regions with hot summers and will often last only 30–50 years in such conditions. It grows soil pH ranging from 4-8.


The twigs are browsed on by whitetail deer, moose and cottontails Deer eat many saplings and may limit regeneration of the species if the deer population is too great. Ruffed grouse and various songbirds feed on the seeds and buds. Due to the thin bark of the tree yellow bellied sapsuckers feed on this tree by drilling holes in the tree and collecting the sap. Broad-winged hawks show a preference for nesting in yellow birch in New York.
Several species of Lepidoptera including the mourning cloak (Nymphalis antiopa) and dreamy duskywing (Erynnis icelus) feed on B. alleghaniensis as caterpillars.
Yellow birch is often associated with eastern hemlock throughout its range due to their similar preferences in habitat. It mostly grows from 0–500 m in elevation but may grow up to 1000 m. It reaches its maximum importance in the transition zone between low elevation deciduous forests and high elevation spruce and fir forests. Due to the thin bark and lack of ability to resprout, it is easily killed by wildfire.
Sugar maple (Acer saccharum) exerts allelopathic effects on seedlings of yellow birch and decreases their growth ability. The inhibitory chemical is exuded from the roots of the sugar maple and has a very short soil half-life, it no longer has effects on birch after 5 days.


Yellow birch is considered the most important species of birch for lumber and is the most important hardwood lumber tree in eastern Canada; as such, the wood of Betula alleghaniensis is extensively used for flooring, furniture, doors, veneer, cabinetry, gun stocks and toothpicks. It was once popular for wagon wheels. Most wood sold as birch in North America is from this tree. Its wood is relatively strong, close grained, and heavy. The wood varies in color from reddish brown to creamy white and accepts stain and can be worked to a high polish. Like most birches, yellow birch wood rots quickly due to its tendency to trap moisture. The cellulose from rotting birch logs was collected by Native Americans and used as a quick fire starter.
In the past, yellow birch has been used for distilling wood alcohol, acetate of lime and for tar and oils. Oil of wintergreen can be distilled from the bark.
The papery, shredded bark, is very flammable due to its oil content and can be peeled off and used as a fire starter even in wet conditions.
Yellow birch can be tapped for syrup similarly to sugar maple, and although the sap has less sugar content, it flows in greater quantity than sugar maple. When the sap is boiled down, the wintergreen evaporates and leaves a syrup not unlike maple syrup. The sap can also be used as is in birch syrup or may be flavored. Tea can also be made from the twigs and inner bark.


Yellow birch has been used medicinally by Native Americans as a blood purifier and for other uses. The Ojibwe make a compound decoction from the inner bark and take it as a diuretic. They also make use of Betula alleghaniensis var. alleghaniensis, taking of the bark for internal blood diseases, and mixing its sap and maple sap used for a pleasant beverage drink. They use the bark of var. alleghaniensis to build dwellings, lodges, canoes, storage containers, sap dishes, rice baskets, buckets, trays and dishes and place on coffins when burying the dead.


Betula nana, the dwarf birch, is a species of birch in the family Betulaceae, found mainly in the tundra of the Arctic region.


It is a monoecious, deciduous shrub growing up to 1–1.2 metres (3 ft 3 in–3 ft 11 in) high. The bark is non-peeling and shiny red-copper colored. The leaves are rounded, 6–20 millimetres (0.24–0.79 in) diameter, with a bluntly toothed margin. The leaves are a darker green on their upper surface. Leaf growth occurs after snow melt and become red in autumn.
The wind-pollinated fruiting catkins are erect, 5–15 millimetres (0.20–0.59 in) long and 4–10 millimetres (0.16–0.39 in) broad.


Betula nana is native to arctic and cool temperate regions of Greenland, Iceland, northern Europe, northern Asia and northern North America and it will grow in a variety of conditions. Outside of far northern areas, it is usually found growing only in mountains above 300 metres (980 ft), up to 835 metres (2,740 ft) in Great Britain and 2,200 metres (7,200 ft) in the Alps. Its northern range limit is on Svalbard, where it is confined to favourable sites. In the UK Betula nana is at its southern range limit, with many populations having declined significantly in recent decades. In southern Sweden the occurrence of Betula nana in Sund, Ydre is deemed a glacial relict.
In general, it favours wet but well-drained sites with a nutrient-poor, acidic soil which can be xeric and rocky. B. nana has a low tolerance for shade.


There are two subspecies:
Betula nana subsp. nana. Canada (Baffin Island), Greenland, northern Europe (south to the Alps at high altitudes), northwestern Asia. Young twigs hairy, but without resin; leaves longer (to 20 mm), usually as long as broad.
Betula nana subsp. exilis. Northeastern Asia, northern North America (Alaska, Canada east to Nunavut). Young twigs hairless or with only scattered hairs, but coated in resin; leaves shorter (not over 12 mm long), often broader than long.


The genome of B. nana  has been sequenced.


Betula nigra, the black birch, river birch or water birch, is a species of birch native to the Eastern United States from New Hampshire west to southern Minnesota, and south to northern Florida and west to Texas. It is one of the few heat-tolerant birches in a family of mostly cold-weather trees which do not thrive in USDA Zone 6 and up. B. nigra commonly occurs in floodplains and swamps.


Betula nigra is a deciduous tree growing to 25–30 meters (80–100 ft) with a trunk 50 to 150 centimeters (20 to 60 in) in diameter. The base of the tree is often divided into multiple slender trunks.
Bark
Bark characteristics of the river birch differ during its youth stage, maturation, and old growth. The bark of a young river birch can vary from having a salmon-pink to brown-gray tint and can be described as having loose layers of curling, paper thin scales. As the tree matures, the salmon-pink color is exchanged for a reddish-brown with a dark grey base color. The scales on a mature tree lack the loose curling and are closely pressed into thick, irregular plates. These scales are slightly separated from the trunk and can shift outward to the side. Once the river birch ages past maturity, the scales become thicker towards the base of the trunk and are divided in deep furrows.
Leaves and fruit
The twigs are glabrous or thinly hairy. There is an absence of terminal buds, and lateral buds often have a hook at the tip of the bud, which differs from other species in the family Betulaceae.  The leaves are alternate, ovate, 4–8 centimeters (1+1⁄2–3+1⁄4 in) long and 3–6 centimeters (1+1⁄4–2+1⁄4 in) broad, with a serrated margin and five to twelve pairs of veins. The upper surface of the leaf is dark green in color, while the underside can be described as having a light yellow-green color. The leaves turn yellow in Autumn. The flowers are wind-pollinated catkins 3–6 centimeters (1+1⁄4–2+1⁄4 in) long, the male catkins pendulous, the female catkins erect. The fruit is unusual among birches in maturing in late spring; it is composed of numerous tiny winged seeds packed between the catkin bracts.


Betula nigra is a tree that falls into the family of Betulaceae, which is commonly known as the Birch or Alder Family. This family comprises six genera (Alnus, Betula, Carpinus, Corylus, Ostrya, and Ostryopsis) and includes alders, birches, hornbeams, and hazelnuts. Species within this family, along with Betula nigra, are shrubs or trees that grow along stream sides or in poorly drained soils throughout the Northern Hemisphere. Betulaceae is included within the order Fagales, which branches from the Rosid clade.


The river birch is often found in low-elevation regions from as north as Massachusetts to as south as northern Florida. It can be found extending west to Kansas and east to the coast where proper habitat conditions occur. As its name depicts, this birch is found along stream-sides. It can also be a prominent species found in forested wetland communities and in areas containing moist soil, such as floodplains.  States include: Alabama, Arkansas, Connecticut, Delaware, Florida, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Massachusetts, Missouri, New Hampshire, New Jersey, New York, North Carolina, Ohio, Oklahoma, Pennsylvania, South Carolina, Tennessee, Texas, Virginia, West Virginia, and Wisconsin.
River birch is best placed in USDA hardiness zones 4-9.


It is listed as threatened in New Hampshire.


In states in which mining is prevalent, the river birch is often used for reclamation and erosion control, as it is well suited for soils that are too acidic for other species of hardwoods. In West Virginia, they have been found to establish within mine refuge sites after being blown from neighboring areas.
As the species occurs predominately in flood plains and along stream banks, it is described as being moderately tolerant of flooding. Saplings were observed to survive up to 30 days of continuous flooding in some regions. While the species is tolerant of excessive water, it is intolerant of shade. Seeds will not germinate without a large amount of direct sunlight.


Seeds are typically produced annually. Seasonal development begins in the fall as male catkins begin to form and mature. The emergence of female catkins corresponds with the return of leaves around early spring. Male and female fruit matures during the spring season or in the early summer months.
Once mature, the seeds are predominantly spread by wind of water from neighboring stream channels.  Seeds spread by water are generally more successful as the moist banks of stream channels, where the seeds are deposited, are favorable for germination and sturdy establishment. Successful germination often occurs in large numbers along sandbars, where alluvial soil is present.


While its native habitat is wet ground, it will grow on higher land, and its bark is quite distinctive, making it a favored ornamental tree for landscape use. A number of cultivars with much whiter bark than the normal wild type have been selected for garden planting, including 'Heritage' and 'Dura Heat'; these are notable as the only white-barked birches resistant to the bronze birch borer (Agrilus anxius) in warm areas of the southeastern United States of America.
Native Americans used the boiled sap as a sweetener similar to maple syrup, and the inner bark as a survival food. The river birch is not typically used in the commercial lumber industry, due to knotting, but its strong, closely grained wood is sometimes used for local furniture, woodenware, and fuel. This species is utilized by many local bird species, such as waterfowl, ruffed grouse, and wild turkey. Many waterfowl use the cover for nesting sites, while the ruffed grouse and wild turkey use the seeds as a food source. Deer have been known to graze on saplings or reachable branches.


The essential oils derived from leaves, inner bark, and buds of B. nigra are mostly composed of eugenol, linalool, palmitic acid, and heptacosane with many more compounds in smaller concentrations. The combined essential oils are phytotoxic to lettuce (Lactuca sativa) and perennial ryegrass (Lolium perenne) seedlings. They have also demonstrated insecticidal, nematicidal, and antibacterial properties.


Betula papyrifera (paper birch, also known as (American) white birch and canoe birch) is a short-lived species of birch native to northern North America. Paper birch is named for the tree's thin white bark, which often peels in paper like layers from the trunk. Paper birch is often one of the first species to colonize a burned area within the northern latitudes, and is an important species for moose browsing. The wood is often used for pulpwood and firewood.


It is a medium-sized deciduous tree typically reaching 20 metres (66 feet) tall, and exceptionally to 40 m (130 ft) with a trunk up to 75 centimetres (30 inches) in diameter. Within forests, it often grows with a single trunk but when grown as a landscape tree it may develop multiple trunks or branch close to the ground.
Paper birch is a typically short-lived species. It handles heat and humidity poorly and may live only 30 years in zones six and up, while trees in colder-climate regions can grow for more than 100 years. B. papyrifera will grow in many soil types, from steep rocky outcrops to flat muskegs of the boreal forest. Best growth occurs in deeper, well drained to dry soils, depending on the location.
In older trees, the bark is white, commonly brightly so, flaking in fine horizontal strips to reveal a pinkish or salmon-colored inner bark. It often has small black marks and scars. In individuals younger than five years, the bark appears a brown red color with white lenticels, making the tree much harder to distinguish from other birches. The bark is highly weather-resistant. It has a high oil content and this gives it its waterproof and weather-resistant characteristics. Often, the wood of a downed paper birch will rot away, leaving the hollow bark intact.
The leaves are dark green and smooth on the upper surface; the lower surface is often pubescent on the veins. They are alternately arranged on the stem, oval to triangular in shape, 4–10 cm (2–4 in) long and about two-thirds as wide. The leaf is rounded at the base and tapering to an acutely pointed tip. The leaves have a doubly serrated margin with relatively sharp teeth. Each leaf has a petiole about 2.5 cm (1 in) long that connects it to the stems.
The fall color is a bright yellow color that contributes to the bright colors within the northern deciduous forest.
The leaf buds are conical and small and green-colored with brown edges.
The stems are a reddish-brown color and may be somewhat hairy when young.
The flowers are wind-pollinated catkins; the female flowers are greenish and 3.8 cm (1+1⁄2 in) long growing from the tips of twigs. The male (staminate) flowers are 5–10 cm (2–4 in) long and a brownish color. The tree flowers from mid-April to June depending on location. Paper birch is monoecious, meaning that one plant has both male and female flowers.
The fruit matures in the fall. The mature fruit is composed of numerous tiny winged seeds packed between the catkin bracts. They drop between September and spring. At 15 years of age, the tree will start producing seeds but will be in peak seed production between 40 and 70 years. The seed production is irregular, with a heavy seed crop produced typically every other year and with at least some seeds being produced every year. In average seed years, 2,500,000 seeds per hectare (1,000,000 per acre) are produced, but in bumper years 86,000,000/ha (35,000,000/acre) may be produced. The seeds are light and blow in the wind to new areas; they also may blow along the surface of snow.
The roots are generally shallow and occupy the upper 60 cm (24 in) of the soil and do not form taproots. High winds are more likely to break the trunk than to uproot the tree.


Betula papyrifera is mostly confined to Canada and the far northern United States. It is found in interior (var. humilus) and south-central (var. kenaica) Alaska and in all provinces and territories of Canada, except Nunavut, as well as the far northern continental United States. Isolated patches are found as far south as the Hudson Valley of New York and Pennsylvania, northern Connecticut, and Washington. High elevation stands are also in mountains to North Carolina, New Mexico, and Colorado. The most southerly stand in the Western United States is located in Long Canyon in the City of Boulder Open Space and Mountain Parks. This is an isolated Pleistocene relict that most likely reflects the southern reach of boreal vegetation into the area during the last Ice Age.


Betula papyrifera is a pioneer species, meaning it is often one of the first trees to grow in an area after other trees are removed by some sort of disturbance. Typical disturbances colonized by paper birch are wildfire, avalanche, or windthrow areas where the wind has blown down all trees. When it grows in these pioneer, or early successional, woodlands, it often forms stands of trees where it is the only species.
Paper birch is considered well adapted to fires because it recovers quickly by means of reseeding the area or regrowth from the burned tree. The lightweight seeds are easily carried by the wind to burned areas, where they quickly germinate and grow into new trees. Paper birch is adapted to ecosystems where fires occur every 50 to 150 years For example, it is frequently an early invader after fire in black spruce boreal forests. As paper birch is a pioneer species, finding it within mature or climax forests is rare because it will be overcome by trees that are more shade-tolerant as secondary succession progresses.
For example, in Alaskan boreal forests, a paper birch stand 20 years after a fire may have 3,000–6,000 trees per acre (7,400–14,800/ha), but after 60 to 90 years, the number of trees will decrease to 500–800 trees per acre (1,200–2,000/ha) as spruce replaces the birch. After approximately 75 years, the birch will start dying and by 125 years, most paper birch will have disappeared unless another fire burns the area.
Paper birch trees themselves have varied reactions to wildfire. A group, or stand, of paper birch is not particularly flammable. The canopy often has a high moisture content and the understory is often lush green. As such, conifer crown fires often stop once they reach a stand of paper birch or become slower-moving ground fires. Since these stands are fire-resistant, they may become seed trees to reseed the area around them that was burned. However, in dry periods, paper birch is flammable and will burn rapidly. As the bark is flammable, it often will burn and may girdle the tree.


The species is considered vulnerable in Indiana, imperiled in Illinois, Virginia, West Virginia, and Wyoming, and critically imperiled in Colorado and Tennessee.


Betula papyrifera has a moderately heavy white wood. It makes excellent high-yielding firewood if seasoned properly. The dried wood has a density of 37.4 lb/cu ft (0.599 g/cm³) and an energy density 20,300,000 BTU/cord (5,900,000 kJ/m³). Although paper birch does not have a very high overall economic value, it is used in furniture, flooring, popsicle sticks, pulpwood (for paper), plywood, and oriented strand board. The wood can also be made into spears, bows, arrows, snowshoes, sleds, and other items. When used as pulp for paper, the stems and other nontrunk wood are lower in quantity and quality of fibers, and consequently the fibers have less mechanical strength; nonetheless, this wood is still suitable for use in paper.
The sap is boiled down to produce birch syrup. The raw sap contains 0.9% carbohydrates (glucose, fructose, sucrose) as compared to 2 percent to 3 percent within sugar maple sap. The sap flows later in the season than maples. Currently, only a few small-scale operations in Alaska and Yukon produce birch syrup from this species.


Its bark is an excellent fire starter; it ignites at high temperatures even when wet. The bark has an energy density of 5,740 cal/g (24,000 J/g) and 3,209 cal/cm³ (220,000 J/cu in), the highest per unit weight of 24 species tested.
Panels of bark can be fitted or sewn together to make cartons and boxes. (A birchbark box is called a wiigwaasi-makak in the Anishinaabe language.) The bark is also used to create a durable waterproof layer in the construction of sod-roofed houses. Many indigenous groups (i.e., Wabanaki peoples) use birchbark for making various items, such as canoes, containers, and wigwams. It is also used as a backing for porcupine quillwork and moosehair embroidery. Thin sheets can be employed as a medium for the art of birchbark biting.


It is the provincial tree of Saskatchewan and the state tree of New Hampshire.
People sometimes vandalize the bark of this tree by carving into it with a knife or by peeling off layers of the bark. Both forms of vandalism can cause unsightly scars on the tree.


Betula pubescens (syn. Betula alba), commonly known as downy birch and also as moor birch, white birch, European white birch or hairy birch, is a species of deciduous tree, native and abundant throughout northern Europe and northern Asia, growing farther north than any other broadleaf tree. It is closely related to, and often confused with, the silver birch (B. pendula), but grows in wetter places with heavier soils and poorer drainage; smaller trees can also be confused with the dwarf birch (B. nana).
Six varieties are recognised and it hybridises with the silver and dwarf birches. A number of cultivars have been developed but many are no longer in cultivation. The larva of the autumnal moth (Epirrita autumnata) feeds on the foliage and in some years, large areas of birch forest can be defoliated by this insect. Many fungi are associated with the tree and certain pathogenic fungi are the causal agents of birch dieback disease.
The tree is a pioneer species, readily colonising cleared land, but later being replaced by taller, more long-lived species. The bark can be stripped off without killing the tree and the bark and the timber is used for turnery and in the manufacture of plywood, furniture, shelves, coffins, matches, toys and wood flooring. The inner bark is edible and it was ground up and used in bread-making in times of famine. The rising sap in spring can be used to make refreshing drinks, wines, ales and liqueurs and various parts of the tree have been used in herbal medicine.


Betula pubescens is commonly known as downy birch, with other common names including moor birch, white birch, European white birch or hairy birch.
It is a deciduous tree growing to 10 to 20 m (33 to 66 ft) tall (rarely to 27 m), with a slender crown and a trunk up to 70 cm (28 in) (exceptionally 1 m) in diameter, with smooth but dull grey-white bark finely marked with dark horizontal lenticels. The shoots are grey-brown with fine downy. The leaves are ovate-acute, 2 to 5 cm (0.8 to 2.0 in) long and 1.5 to 4.5 cm (0.6 to 1.8 in) broad, with a finely serrated margin. The flowers are wind-pollinated catkins, produced in early spring before the leaves. The fruit is a pendulous, cylindrical aggregate 1 to 4 cm (0.4 to 1.6 in) long and 5 to 7 mm (0.2 to 0.3 in) wide which disintegrates at maturity, releasing the individual seeds; these seeds are 2 mm (0.08 in) long with two small wings along the side.


B. pubescens is closely related to, and often confused with, the silver birch (B. pendula). Many North American texts treat the two species as conspecific (and cause confusion by combining the downy birch's alternative vernacular name, white birch, with the scientific name B. pendula of the other species), but they are regarded as distinct species throughout Europe.
Downy birch can be distinguished from silver birch with its smooth, downy shoots, which are hairless and warty in silver birch. The bark of the downy birch is a dull greyish white, whereas the silver birch has striking white, papery bark with black fissures. The leaf margins also differ, finely serrated in downy birch, coarsely double-toothed in silver birch. The two have differences in habitat requirements, with downy birch more common on wet, poorly drained sites, such as clays and peat bogs, and silver birch found mainly on dry, sandy soils.
In more northerly locations, downy birch can also be confused with the dwarf birch (Betula nana), both species being morphologically variable. All three species can be distinguished cytologically, silver birch and dwarf birch being diploid (with two sets of chromosomes), whereas downy birch is tetraploid (with four sets of chromosomes). In Iceland, dwarf birch and downy birch sometimes hybridise, the resulting plants being triploid (with three sets of chromosomes).


Betula pubescens has a wide distribution in northern and central Europe and Asia. Its range extends from Newfoundland, Iceland, the British Isles and Spain eastwards across northern and central Europe and Asia as far as the Lake Baikal region in Siberia. The range extends southwards to about 40°N, its southernmost limit being Turkey, the Caucasus and the Altai Mountains. It is a pioneer species which establishes itself readily in new areas away from the parent tree. This allows other woodland trees to become established and the birch, a short-lived tree, eventually gets crowded out as its seedlings are intolerant of shady conditions.
Downy birch extends farther north into the Arctic than any other broadleaf tree. Specimens of the subarctic populations are usually small and very contorted, and are often distinguished as arctic downy birch or mountain birch, B. p. var. pumila. (not to be confused with B. nana). This variety is notable as being one of very few trees native to Iceland and Greenland, and is the only tree to form woodland in Iceland. At one time the island is thought to have been covered in downy birch woodland, but that cover is reduced to about one percent of the land surface today.


Three varieties are recognised, the nominate Betula pubescens var. pubescens, B. p. var. litwinowii (distributed in the Caucasus and Turkey) and B. p. var. pumila (arctic downy birch or mountain birch, formerly called B. p. subsp. tortuosa). The latter has arisen from the hybridization of var. pubescens and B. nana (dwarf birch) and is characterised by its shrubby habit, smaller leaves, resinous glands and the smaller wings on the fruit. A number of cultivars have been grown but many are no longer in cultivation. They include "Armenian gold", "Arnold Brembo" (scented foliage), crenata nana (shrubby and dwarf), incisa (lobed foliage), integrifolia (unlobed foliage), murigthii (shrubby with doubly serrate leaves), ponitica (hairless), undulata (leaf margins waxy), urticifolia (nettle-leaved), variegata (variegated) and "Yellow wings". Two others, described by the German botanist Ernst Schelle in 1903, are also lost; pendula, a cultivar with a leader and weeping branches, and pendula nana, which grows into an umbrella-shaped tree with weeping branches but no leader. Betula pubescens 'Rubra' has maroon foliage.


The larva of the autumnal moth (Epirrita autumnata) feeds on the foliage of Betula pubescens and other tree species. In outbreak years, large areas of birch forest can be defoliated by this insect. Damage to the leaf tissue stimulates the tree to produce chemicals that reduce foliage quality, retarding the growth of the larvae and reducing their pupal weights.
In Greenland, about seventy species of fungi have been found growing in association with B. pubescens, as parasites or saprobes on living or dead wood. Some of the most common fungi include Ceriporia reticulata, Chondrostereum purpureum, Exidia repanda, Hyphoderma spp, Inonotus obliquus, Inonotus radiatus, Mycena galericulata, Mycena rubromarginata, Panellus ringens, Peniophora incarnata, Phellinus lundellii, Radulomyces confluens, Stereum rugosum, Trechispora spp., Tubulicrinis spp. and Tyromyces chioneus.
Birch dieback disease, associated with the fungal pathogens Marssonina betulae and Anisogramma virgultorum, can affect planted trees, while naturally regenerated trees seem less susceptible. This disease also affects Betula pendula and in 2000 was reported at many of the sites planted with birch in Scotland during the 1990s.


Biblis hyperia, the red rim or crimson-banded black, is a species of brush-footed butterfly (family Nymphalidae) that is native to the lower Rio Grande Valley of Texas in the United States, Mexico, the Caribbean, Central America, and South America as far south as Paraguay. Its genus Biblis is so far monotypic, but at least one other undescribed species is suspected to exist.
They can be seen flying between March and November in subtropical forest. The immature larvae feed on Tragia volubilis.


Adults have a velvety-black forewing with a gray hindwing. The hindwing has a pinkish-red band. The caterpillars of this species are gray brown with raised green marks and spikes.
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Listed alphabetically:
B. h. aganisa Boisduval, 1836
B. h. hyperia (Cramer, [1779])
B. h. laticlavia (Thieme, 1904)
B. h. nectanabis (Fruhstorfer, 1909)
B. h. pacifica (Hall, 1928)
An unnamed species has been identified in Peru.


Bicyrtes quadrifasciatus, the four-banded stink bug hunter wasp, is a species of sand wasp in the family Crabronidae. It is found in North America.


Bidens aristosa is a North American species of plants in the sunflower family. Common names include bearded beggarticks, western tickseed, long-bracted beggarticks, tickseed beggarticks, swamp marigold, and Yankee lice. It is native to eastern and central United States and south-central Canada, from Maine south to Florida and west as far as Ontario, Texas, and Nebraska. It grows in wet meadows and abandoned fields.
Bidens aristosa is an annual herb occasionally reaching 150 cm (5 feet) in height. It has numerous yellow flower heads with both ray florets and disc florets. Fruits are dry achenes bearing barbs that get caught in fur or clothing, thus aiding in the plant's dispersal. The plant attracts native bees.


Bidens cernua is a plant species in the sunflower family, widespread across much of Eurasia and North America. It is commonly called nodding beggarticks or nodding bur-marigold,
Bidens cernua sometimes grows as high as 400 cm (160 inches) tall in favorable conditions. The leaves are sessile with coarsely-toothed margins. The name "cernua" means "nodding", or "hanging". This refers to the fact that the flower heads are sometimes oriented horizontally or downwards. The plant does best in wet habitats such as swamps, marshes, and flood plains.
The seeds can be eaten by ducks.


Bidens pilosa is a branched annual forb of gracile habit, growing up to 1.8 meters tall. It grows aggressively on disturbed land and often becomes weedy. The leaves are all oppositely arranged and range from simple to pinnate in form, the upper leaves with three to five dentate, ovate-to-lanceolate leaflets. The petioles are slightly winged.
The plant may flower at any time of the year, but  mainly in summer and autumn in temperate regions. The flowers are small heads borne on relatively long peduncles. The heads consist of about four or five broad white ray florets (ligules),  surrounding many tubular yellow disc florets without ligules that develop into barbed fruits.
The fruits are slightly curved, stiff, rough black rods, tetragonal in cross section, about 1 cm long, typically with two to three stiff, heavily barbed awns at their distal ends.
The infructescences form stellate spherical burrs about one to two centimeters in diameter. The barbed spines of the achenes get stuck in the feathers, fur, fleeces, clothing, etc. of people or animals that brush against the plant.
It is an effective means of seed dispersal by zoochory, as the fruits are transported by animals. This mechanism has helped the plant become a noxious weed in temperate and tropical regions. The barbed awns can injure flesh.


The species is native to tropical America, widely naturalized throughout the warm temperate and tropical regions of the world. A weed of gardens, woodlands, and waste areas.


Its many English common names include black-jack, beggarticks, hairy beggarticks, cobbler's pegs, devil's needles, hairy bidens, Spanish needle, farmers friend, Devils Pitchfork, hitch hikers and sticky beaks.


Although Bidens pilosa is primarily considered a weed, in many parts of the world it is also a source of food and medicine. The leaves have a resinous flavor, and are eaten raw, in stews, or dried for storage. It is especially important in eastern Africa, where it is known as michicha.
In Vietnam, during the Vietnam War, soldiers adopted the herb as a vegetable, which led to it being known as the "soldier vegetable".
It is susceptible to hand weeding if small enough, even then must be bagged, and thick mulches may prevent it from growing.
In traditional Chinese medicine, this plant is considered a medicinal herb, called xian feng cao (Chinese: 咸豐草). In traditional Bafumbira medicine, this plant is applied on a fresh wound and is known as inyabalasanya. Extracts from Bidens pilosa are used in Southern Africa for malaria.


Almost two hundred compounds have been isolated from B. pilosa, especially polyacetylenes and flavonoids. The plant contains the chalcone okanin and ethyl caffeate, a hydroxycinnamic acid.


Bignonia capreolata is a vine commonly referred to as crossvine.  The common name refers to the cross-shaped pattern revealed when the stem is cut; this pattern results from four radial wedges of phloem embedded within the stem’s xylem.  It is native to the central and southern United States.  The vine climbs without twining but does produce tendrils.  It produces long tubular flowers which are red and yellow and frequently have a mocha fragrance.  The leaves are dark green to almost purple and produced as opposite pairs with terminal tendrils.  The vine often climbs very high, with leaves only remaining on the uppermost portion of the plant. Crossvine can spread aggressively through stolons and may need to be managed in garden or domestic settings.
There was for some time confusion surrounding the name of this plant, which was apparently sometimes referred to as "Bignonia crucigera", a name more properly referring to a different plant altogether.


One 18th century report describes a medicinal use for cross-vine by the Cherokee people:
"The vines or climbing stems of the climber (Bigonia Crucigera)  are equally divided longitudinally into four parts by the same number of their membranes somewhat resembling a piece of white tape by which means, when the vine is cut through and divided traversely, it presents to view the likeness of a cross. This membrane is of a sweet, pleasant taste. The country people of Carolina crop these vines to pieces, together with china brier and sassafras roots, and boil them in their beer in the spring, for diet drink, in order to attenuate and purify the blood and juices. It is a principal ingredient in Howard's famous infusion for curing the yaws, etc., the virtues and use of which he obtained from Indian Doctors."
In 2012, researchers at Bastyr University published a paper revealing that they had identified the indole alkaloid reserpine in Crossvine.


Bistorta bistortoides (American bistort, western bistort, smokeweed, mountain meadow knotweed, mountain buckwheat or mountain meadow buckwheat) is a perennial herb in the buckwheat and knotweed family  Polygonaceae. The species name remains unresolved.
Bistorta bistortoides is distributed throughout the Mountain West in North America from Alaska and British Columbia south into California and east into the Rocky Mountains.
Bistorta bistortoides grows from foothills to above the timberline, although plants growing above 7,500 feet (2250 m) are smaller and seldom reach more than 12 inches (30 cm) in height. Plants in other areas may reach over half a meter–1.5 feet (20–60 cm) tall. The leaves are leathery and up to 40 centimeters (3 feet) long, and are mostly basal on the stem. The dense cylindrical to oblong inflorescence is packed with small white to pinkish flowers, each a few millimeters wide and with protruding stamens. Rodents and bears consume the roots, and elk and deer browse the foliage.
American bistort was an important food plant used by Native Americans living in the Mountain West, including Blackfoot and Cheyenne peoples. The roots are edible either raw or fire-roasted with a flavor resembling chestnuts.  The seeds can be dried and ground into flour and used to make bread. They were also roasted and eaten as a cracked grain. The young leaves can be eaten raw or cooked.


Bistorta officinalis (synonym Persicaria bistorta), known as bistort, common bistort, European bistort or meadow bistort, is a species of flowering plant in the dock family Polygonaceae native to Europe and northern and western Asia. Other common names include snakeroot, snake-root, snakeweed and Easter-ledges.


Bistorta officinalis is an herbaceous perennial growing to 20 to 80 centimetres (8 to 31 in) tall by 90 cm (35 in) wide. It has a thick, twisted rootstock which has probably given it its common name of snakeroot. The foliage is normally basal with a few smaller leaves produced near the lower end of the flowering stems. The leaves usually hairless; the basal ones are longish-oval with long winged stalks and rounded or heart-shaped bases; the upper ones are few and are triangular, tapered and stalkless. There are stipules at their base which are fused into a sheath surrounding the stem. The petioles are broadly winged. The inflorescence is a spike. The plant blooms from late spring into autumn, producing tall, erect, unbranched and hairless stems ending in single terminal racemes that are club-like spikes, 5–7 cm (2–3 in) long, of rose-pink flowers. The individual flowers are pink with five perianth segments, eight stamens, three fused carpels and three free styles. The fruit is a glossy black nut. Flowering takes place in June and July. The plant grows in moist soils and under dry conditions goes dormant, losing its foliage until adequate moisture exists again.


The generic placement of this species was historically in flux, having been placed in Polygonum or Persicaria but is now accepted as Bistorta.


The Latin name bistorta, from bis ("twice") + torta ("twisted"), refers to the twisted appearance of the root.
Numerous other vernacular names have been recorded for the species in historical texts, though none is used to any extent. Many of the following refer to the plant's use in making puddings:
Adderwort
Dragonwort
Easter giant
Easter ledger
Easter ledges
Easter magiant
Easter man-giant
Gentle dock
Great bistort
Osterick
Oysterloit
Passion dock
Patience dock
Patient dock
Pink pokers
Pudding grass
Pudding dock
Red legs
Snakeweed
Twice-writhen
Water ledges


Bistort is a native of Europe but is often cultivated and has become naturalized in other parts of the world such as in the United States in New England. It is typically found growing in moist meadows, nutrient-rich wooded swamps, forest edges, wetlands, parks, gardens and disturbed ground.


This species is grown as an ornamental garden plant, especially the form 'Superba' which has larger, more showy flowers, and has gained the Royal Horticultural Society's Award of Garden Merit. It is suitable for use as a marginal or in bog gardens. Bistort has been cultivated as a vegetable, its roots, leaves and young shoots being steamed or boiled. Many of its occurrences in the wild may be as a garden escape.


It has also been used traditionally for medicinal purposes. The roots are rich in tannic and gallic acids and both these and the leaves have been used to treat wounds.
In Northern England the plant was used to make a bitter pudding in Lent from a combination of the leaves, oatmeal, egg and other herbs. It is the principal ingredient of dock pudding or Easter-Ledge pudding. The root of Bistort can be used to produce an astringent that was used in medicine. The roots are also eaten in Russia and northern Asia.


Bituminaria bituminosa, the Arabian pea or pitch trefoil, is a perennial Mediterranean herb species in the genus Bituminaria.
The pterocarpans bitucarpin A and B can be isolated from the aerial parts of B. bituminosa.
It has several potential uses: (i) forage crop, (ii) Phytostabilization of heavy metal contaminated or degraded soils, (iii) Synthesis of furanocoumarins (psoralen, angelicin, xanthotoxin and bergapten), compounds of broad pharmaceutical interest.
It is easily recognizable by the characteristic smell of bitumen from its leaves. This strong tar-like characteristic aroma appears to be the result of a combination of several substances such as phenolics, sulphurated compounds, sesquiterpenes and probably short-chain hydrocarbon. Total polyphenols content was < 2% and the condensed tannins was <0.8% in a dry weight basis.


The Arabian pea was first legitimately described in 1753 by Carl Linnaeus in his Species Plantarum, the work which is now internationally accepted as the starting point of modern botanical nomenclature, and he called it Psoralea bituminosa. Philipp Conrad Fabricius described the genus Bituminaria in 1759, that was suggested by Lorenz Heister earlier, but without a proper description. In 1787, Friedrich Kasimir Medikus described a woody form as Asphalthium frutescens and a herbaceous form as Asphalthium herbaceum. Jules Pierre Fourreau considered that Linnaeus was the earliest and he made the new combination Asphalthium bituminosum in 1868. When Charles Howard Stirton revised some of the Papilionoideae of southern Africa in 1981, he reassigned many species that had been included in Psoralea to several new genera, including the Arabian pea. He considered Asphalthium a later synonym for Bituminaria and therefore created the new combination Bituminaria bituminosa.


Blastobasis glandulella is a species of moth of the family Blastobasidae. It is found in the  eastern United States and southern Ontario, Canada. It has also been recorded in California. In Europe, it has been recorded from Austria, Germany, the Czech Republic, Italy, Slovakia and Croatia.
It is commonly known as the acorn moth, but this can also refer to the tortrix moth Cydia splendana from Europe.
The wingspan is 15–25 mm. Adults have gray to grayish-brown forewings with a pale diffuse line bordered distally by dark band. There is also a black median dot and two black reniform dots, which form a triangle. The terminal line is composed of dark dots. The hindwings are shiny gray with dark veins and a fringe of long hair-like scales. They are on wing from April to September.
The larvae feed inside acorns and chestnuts.


Austroblechnum lanceolatum, synonym Blechnum chambersii, is a species of fern within the family Blechnaceae, found in Australia, New Zealand, Samoa and Fiji.
A. lanceolatum is commonly called lance water fern, and in New Zealand it is also referred to by its Māori names, nini and rereti.


Parablechnum novae-zelandiae, synonym Blechnum novae-zelandiae, commonly known as palm-leaf fern or kiokio, is a species of fern found in New Zealand. It can often be found growing in clay soil on embankments and roadsides.
P. novae-zelandiae has long fronds that grow up to 2 metres long by 50 cm wide. They are pink when new and as they age they turn green and darken.


Austroblechnum penna-marina, synonym Blechnum penna-marina, known as Antarctic hard-fern, alpine water fern and pinque (Chilean Spanish), is a species of fern in the family Blechnaceae, with a natural range from the Araucanía Region to the south and from the coast to the tree line of the Magellanic forests in Chile and adjacent areas of Argentina. It is also found in New Zealand, Australia and some Pacific islands.  It is evergreen and grows to 20 cm (8 in).
In cultivation, this hardy species has gained the Royal Horticultural Society's Award of Garden Merit.


Parablechnum procerum, synonym Blechnum procerum, commonly known as mountain kiokio or small kiokio, is a species of fern found in New Zealand. It is found from lowland to alpine areas among forest, scrub and tussock.
P. procerum usually grows to a height of between 30 and 50 cm.


Blepharomastix ranalis, the hollow-spotted blepharomastix moth,  is a species of grass moth of the family Crambidae found in the eastern and southern United States, and Mexico.


Blephilia hirsuta is an herbaceous perennial of the mint family Lamiaceae native to eastern North America. It is commonly called hairy wood-mint or hairy pagoda plant.


Hairy wood mint is a perennial plant that is normally 30 to 120 cm (12 to 47 inches) tall. The central stem is covered with long white hairs and ends in several whorls of flowers.
The flowers can be either light blue, pale purple or white with purple spots. Each flower is about 1 cm (1⁄2 inch) long with light green sepals, two main 'lips', two visible stamens, and a style that is divided at its tip. The flowers appear in the summer for roughly a month and a half.
Arranged oppositely along the stem, the leaves of hairy wood mint are long but thin, becoming wider near the base of the leaf. They are pleasantly fragrant. The petioles are 1 to 3 cm (1⁄2 to 1+1⁄4 inches) and are covered with little hairs. Out of all the plants in this genus, Blephilia hirsuta has the largest leaves. The stems grow from a system of rhizomes with fibrous roots.


The German-American botanist Frederick Pursh described the hairy wood mint as Monarda hirsuta in his 1814 work Flora americae septentrionalis, before George Bentham gave it its current binomial name. The species name hirsuta is Latin for "hairy".


In Canada, hairy wood mint can be found in southern Quebec and Ontario. It is common throughout the eastern United States, including Connecticut, Florida, Indiana, Kentucky, Minnesota, Nebraska, North Carolina, Tennessee, West Virginia, and Wisconsin.
Hairy wood mint prefers rich moist soil in hardwood forests, along streams and rivers, in forest openings and thickets underlain by limestone, and is occasionally found near wetlands. Hairy wood mint likes partial sun or light shade. Forests with infrequent, low-intensity disturbances (i.e., gap dynamics) are ideal.


Hairy wood mint is not generally used as food by humans, but it is often planted in gardens for its beauty and pleasant aroma; when the leaves are crushed or damaged they give off a minty scent. It may, however, have some beneficial medicinal properties, given that a related species (Blephilia ciliata) has historically been used by the Cherokee as a poultice to treat headaches.


Many different types of bees (e.g., honeybees, mason bees, and miner bees), flies (e.g., bee-flies and syrphids), and butterflies (e.g., skippers) pollinate the flowers of hairy wood mint. Many of these pollinators pollinate the hairy wood mint because they get a nectar reward, although some are after the pollen itself. The foliage "probably isn't attractive to mammalian herbivores as a food source."


Over most of its range Blephilia hirsuta is a secure species, but in Connecticut it is listed as a species of 'special concern', in Vermont it is 'threatened', and in Massachusetts Hairy wood mint is an endangered species.  Unfortunately, the exact needs for conservation management are not known.


Bloomeria crocea, also known as goldenstar, is a geophyte  from southern California and northern Baja California. It is found along hillsides, in grassland and chaparral edges, and in dry flats.


The corms of Bloomeria crocea have a fibrous exterior and usually produces only one leaf.  Plants produce six-petaled golden flowers that are clustered in a loose umbel.  When the three-lobed stigma is fertilized, Bloomeria produces capsules that contain small black seeds.  The seeds then require three to four years to become a mature plant.


Growing in full sun, Bloomeria crocea prefers porous soil and semi-dry conditions, in the Peninsular, Transverse, and southern California Coast Ranges, and on the Channel Islands. Its distribution is found along the southern coast from Santa Barbara County and western Kern County, through Southern California, down into Baja California.


Three varieties are currently recognised:
B. crocea var. aurea
B. crocea var. crocea
B. crocea var. montana


Boa imperator or Boa constrictor imperator is a large, heavy-bodied, nonvenomous species of snake, of the boa genus, that is commonly kept in captivity. Boa imperator is part of the family Boidae and is found in Mexico, Central America and South America west of the Andes Mountains (primarily Colombia). It is commonly called the common boa, northern boa, Colombian boa and common northern boa and is frequently and erroneously referred to as the  red-tailed boa  or  Colombian red-tailed boa, especially in the pet trade.


Boa imperator is wide-ranging, with animals living in both Central America and northern parts of South America. As a result, the appearance of this snake varies greatly depending on the specific locality. As one of the smaller Boa species, they average between 1.3 m (4.2 ft.) and 2.5 m (8.2 ft.) in length when fully grown, but have been known to reach 3.7 m (12 ft.). They usually weigh around 6 kg (13 lb), although females are significantly larger than males. Lifespan in the wild is around 20–30 years, but 40 can be exceeded in captivity.
Although Boa imperator exhibits almost identical patterns to Boa constrictor, this species often has a darker tail, usually dark brown or very dark red. They are, however, usually just as colorful as their counterparts and, like the larger boas, can be bred into a variety of different colors, given the right conditions to breed.
Notably, the species is one of only two in snakes to have a confirmed XY sex chromosome system.
One population is found on the Cayos Cochinos (Hog Islands) off the northern shore of Honduras. These are naturally hypomelanistic, which means that they have reduced melanin, thus are more lightly colored, although they retain the distinctive darker tail that is characteristic of most members of this species. The color of the tail may vary from salmon-pink to orange.
Another well known population of Boa imperator is the population from Nicaragua. While not as small as the dwarf insular island populations, adults are still smaller than the larger B. c. constrictor. The size of a mature female Nicaraguan boa is 1.1 m and 1.9 kg, while the larger female B. c. constrictor is not mature until she reaches 1.6 m and 4.5 kg. Nicaraguan individuals typically have a compact saddle pattern on their backs that is often circular in shape. These boas have a reputation for being "nippy", with some individuals being quick to bite in self-defense.
Mainland specimens from Colombia can be among the larger boas, but this subspecies also includes a number of dwarf insular populations, such as those from various Caribbean islands. These populations represent the smallest members of the species.


Boa imperator has 55-79 dorsal scales, 225-253 ventral scales, 47-69 subcaudal scales, 18-22 supralabial scales and 1-2 anal scales.


Boa imperator is commonly confused with other Boa species, such as Boa constrictor.


Boa imperator was formerly classified as a subspecies of Boa constrictor until DNA sequencing identified B. c. imperator as a separate genetic lineage with 5-7% divergence from B. constrictor. Widespread acceptance is still pending, but several publications have acknowledged the new name since this finding.
Boa imperator from the Pacific coast of Mexico has been separated as another species, Boa sigma.
Certain Boa populations, such as Hog Island, Corn Island, Tarahumara, Ecuador, etc., are currently classified as different 'locales' of Boa imperator. These locales have yet to be reclassified as official subspecies.


Boa imperator can be found in some regions of Mexico, Central America and northwestern Colombia, as well as several islands along the coasts of these areas. The type locality given is "l'Amerique meridionale, principalement au Mexique" (Central America, principally Mexico).
Boa imperator prefers to live in rainforests due to humidity, temperature, cover from potential predators and ample prey.


Boa imperator generally live on their own, and do not interact with any other snakes unless they want to mate. They are crepuscular, but they may bask during the day when night-time temperatures are too low. As semi-arboreal snakes, young Boa imperator may climb into trees and shrubs to forage; however, they become mostly terrestrial as they become older and heavier. Boa imperators strike when they perceive a threat. Their bite can be painful, especially from large snakes, but is rarely dangerous to humans. Specimens from Central America are more irascible, hissing loudly and striking repeatedly when disturbed, while those from South America tame down more readily. Like all snakes, Boa imperators in a shed cycle are more unpredictable, because the substance that lubricates between the old skin and the new makes their eyes appear milky, blue or opaque, so that the snake cannot see very well, causing it to be more defensive than it might be otherwise.


Boa imperator, like most Boa species, has a varied diet that consists mainly of mammals, birds and lizards.  The size of the prey item increases as it ages.
Boa imperator, like other Boa species, are crepuscular  ambush predators. They use constriction as the primary means of incapacitating their prey.


Boa imperator is one of the most common snakes kept in captivity; this is mainly due to their calm dispositions, impressive size potential and variety of color and pattern choices. Captive common boas often tolerate being handled for extended periods. Captive Boa imperator are generally fed pre-killed rodents in an attempt to reduce damage to the specimen from the prey and for the sake of being more humane.
This snake species has been a common species in the global pet trade since the 1980s, with 115,131 individuals being exported between 1989 and 2000.  Wild caught specimens will often contain parasites, both internal and external. The most common parasite is Ophionyssus natricis or the "reptile mite".
Boa imperator captive breeders will often breed for a specific color or "morph". There are several color and pattern morphs available in the pet trade, such as albino, hypomelanistic, motley and jungle individuals.


Except B.c.occidentalis which is included in Appendix I.


Boehmeria cylindrica, with common names false nettle and bog hemp, is an herb in the family Urticaceae.  It is widespread in eastern North America and the Great Plains from New Brunswick to Florida to Texas to Nebraska, with scattered reports of isolated populations in New Mexico, Arizona, and Utah, as well as in Bermuda, Mexico, Central America, the West Indies, and South America.
The plant is an herb or subshrub up to 160 cm tall, usually monoecious, but rarely dioecious. Leaves are usually opposite, though occasionally alternate, and the inflorescence is a spike with a tuft of small bracts at the apex.


B. cylindrica is a deciduous and occasionally dioecious growing plant. The plant grows to be 0.5 to 1.0 m in height with opposite leaf arrangement. Spike-like hairs are in the leaf axils. Leaves are ovate in shape and 6–8 cm in length and 3–4 cm in width. Flowers are green or greenish white in color and the flowers appear from the axils of the upper leaves. Small, oval-shaped seeds are covered in small, hook-like hairs. Once mature, the seeds are dark brown. The inflorescences resemble spikes and can be from 1–3 cm in length. Male and female flowers typically grow on separate plants. Male flowers are more prominently distributed among the spikes in bunches. The female flowers are less continuously distributed along the spikes.


Some of the synonyms and intraspecific taxa are: Boehmeria austrina Small, Boehmeria cylindrica (L.) Sw. var. drummondiana (Weddell) Weddell, and Boehmeria cylindrica (L.) Sw. var. scabra Porter.


B. cylindrica can be found across the North American continent into Central and South America. It is native to northeastern Canada through the majority of the United States from Maine to Florida and stretching towards South Dakota to California.


B. cylindrica can be found in wet to mesic deciduous woodland habitats. The plant flourishes the most in floodplain and bottomland areas.


B. cylindrica is wind pollinated, so plants are fertilized by pollen carried by the wind. Thus, the flowers do not attract many insects. Larvae of the fly Neolasioptera boehmeriae, form small galls in the shape of spindles. Flowering season for B. cylindrica is during the summer to fall. During flowering season, pollen acts as an allergen to some.
It is a larval host to the eastern comma, the question mark, and the red admiral.


The generic name Boehmeria honors the German botanist, Georg Rudolf Boehmer (1723-1803). The specific name cylindrica is based on its generally cylindrical spikes located in the leaf axils.


Boerhavia coccinea is a species of flowering plant in the four o'clock family which is known by many common names, including scarlet spiderling, red boerhavia, and in Spanish, hierba del cancer and hierba de la hormiga.
This is a widespread plant, whose native range is not certain, but probably includes the southwestern United States and parts of Mexico. It is present across the southeastern United States, where it may be naturalized. It is also present in Africa, Asia, Australia, and South America. It is present on many Pacific islands, including the Hawaiian Islands, where it is an invasive species and a noxious weed.
This plant grows in a wide variety of habitats, including disturbed areas as a common roadside weed. It is a low-lying, sprawling perennial herb producing reaching stems which can exceed a meter in length. The stems are somewhat hairy and sticky with glands. The generally oval-shaped leaves are held on short petioles. They are wavy along the edges and may have reddish margins. The inflorescence is a small head of tiny frilly flowers, each just a few millimeters long. The flowers are often bright scarlet to red-violet in color but can be shades of pink, yellow, or white.


The leaves and roots of B. coccinea are used medicinally in countries including Cameroon, Ethiopia, Namibia, Nigeria, Tanzania, Mexico, Brazil, Argentina, and Paraguay. It is also eaten by humans and used as animal feed. A flour can be made from its seeds.


The buff-tailed coronet (Boissonneaua flavescens) is a species of hummingbird in the "brilliants", tribe Heliantheini in subfamily Lesbiinae. It is found in Colombia, Ecuador, and Venezuela.


The buff-tailed coronet shares genus Boissonneaua with two other coronets, the chestnut-breasted (B. matthewsii) and velvet-purple (B. jardini). It has two subspecies, the nominate B. f. flavescens and B. f. tinochlora.


The buff-tailed coronet is 11 to 12 cm (4.3 to 4.7 in) long and weighs 7.3 to 8.8 g (0.26 to 0.31 oz). Both sexes have a short, straight, black bill and a small white spot behind the eye. Males of the nominate subspecies are mostly shining green, with a buff belly spotted with green. The underwing coverts are cinnamon and show in flight. The central tail feathers are bronzy and the rest buff with bronze tips and edges. It has small white tufts on the legs. The nominate female has more buff on the underparts and the bronze of the tail is less extensive. The buff parts of both sexes of B. f. tinochlora have a cinnamon cast and there is more bronze on the tail feathers' tips.


The nominate subspecies of buff-tailed coronet is found from the Andes of western Venezuela's Mérida state south and west through all three Andean ranges of Colombia. B. f. tinochlora is found from southwestern Colombia south along the west slope of the Andes as far as Cotopaxi Province in central Ecuador and also in a few places on Ecuador's eastern Andean slope. The species inhabits the interior and edges of humid to wet montane forest, cloudforest, and elfin forest. It also occurs in more open shrubby landscapes. In elevation it ranges from 2,000 to 3,500 m (6,600 to 11,500 ft).


The buff-tailed coronet is highly territorial, though it may share feeding at a flowering tree with other hummingbirds. It typically forages in the mid-story but also feeds in the canopy. Its main nectar sources are in genera Cavendishia, Palicourea, Disterigma, and Huilaea. It feeds by clinging to the flower, holding its wings open for a second or two after landing. In addition to nectar it captures small insects by hawking from a perch.


Buff-tailed coronet breeding behavior has been recorded between November and March. It builds a cup nest of moss and lichen that is usually attached to a branch between 3 and 10 m (10 and 30 ft) above the ground. The female incubates the clutch of two eggs.


What is thought to be the buff-tailed coronet's song is "a continuous series of single high-pitched 'tsit' notes". It sometimes sings with several others of its species nearby. It also makes a "squeaky twittering, with rising piping notes and stuttering rattles", especially when interacting with other hummingbirds.


The IUCN has assessed the buff-tailed coronet as being of Least Concern, though its population size and trend are not known. No immediate threats have been identified. It is considered rare to locally common in different parts of its large range. It occurs in at least one protected area in Colombia.


Bolboschoenus maritimus is a species of flowering plant from family Cyperaceae. Common names for this species include sea clubrush, cosmopolitan bulrush, alkali bulrush, saltmarsh bulrush, and bayonet grass. It is found in seaside wetland habitats over much of the world. It is widespread across much of temperate and subtropical Africa, Asia,  Europe,  North America, South America and various islands.


As a halophyte, B. maritimus is usually found in saline habitats, including the northern coast of the North and Baltic Sea, Scandinavia, and in coastal western and southern Europe, as well as inland in northern Poland, Pannonia, and as far east as the Ural Mountains. B. maritimus often dominates in areas with saline, muddy substrates that are rich in minerals with substantial water level fluctuations that typically flood in spring and early summer. However these habitats have grown in economic importance and are used intensively for livestock grazing, which has led to the disappearance of B. maritimus from its historical range, exacerbated by land reclamation, invasive species, and conversion to arable land.


Boloria chariclea, the Arctic fritillary or purplish fritillary, is a butterfly of the family Nymphalidae. It is found in the northern parts of the Palearctic and Nearctic realms.


The uppersides of the wings are orange brown with small dark markings in neat rows. The underside of the forewing is orange with dark markings. The underside of the hindwing has a margin of small white spots topped with brown. Inside this are black inwardly pointing triangles with scant white areas. The median band is pale yellow brown to rusty brown mottled with white and with wavy, sometimes broken, black lines. The length of the forewings is about 17 mm (0.67 in). The butterfly flies from July to August depending on the location.


The Arctic fritillary has a Holarctic distribution. In Europe it is found in northern Lapland and Russia. In North America it is found in Alaska and much of Canada, the north Cascades, the Rocky Mountains southwards to Utah and northern New Mexico, northern Minnesota, northern Maine and the White Mountains of New Hampshire. Its typical habitat is tundra, taiga, alpine meadows, stream verges and acid bogs.


The males patrol along the edges of bogs and in valleys and wait for the arrival of females. The eggs are laid singly underneath the leaves of the host plant. In North America the larvae feed on viola species, dwarf willows (Salix) and possibly blueberries (Vaccinium) while in Europe it is believed to feed on yellow wood violet (Viola biflora) and Arctic white heather (Cassiope tetragona). Depending on location, the larvae take one or two years to develop into adults, newly hatched caterpillars hibernate during the first winter and fourth-stage caterpillars hibernate during the second.


B. c. chariclea Arctic Europe
B. c. arctica (Zetterstedt, 1839)   Arctic Asia, Wrangel Island, Chukotka
B. c. butleri (Edwards, 1883)   Arctic America, Chukotka, Kamchatka
B. c. boisduvalii (Duponchel, 1832)   Alaska, Alberta, Labrador, Newfoundland, Minnesota, British Columbia
B. c. rainieri  (Barnes & McDunnough, 1913)   Washington
B. c. grandis  (Barnes & McDunnough, 1916)   North British Columbia, Ontario
B. c. montina  (Scudder, 1863)
B. c. helena   (Edwards, 1871)   Rocky Mountains


Boloria dia, the Weaver's fritillary or violet fritillary,  is a butterfly in the family Nymphalidae. The name Weaver's fritillary is in honor of Richard Weaver, an English insect collector who claimed to have obtained the specimen within ten miles of Birmingham around 1820. However, B. dia is uncommon in England and the few specimens known from there are thought to be from possibly accidental introductions.


The adult is a small fritillary with typically chequered orange-brown upperside and a submarginal row of triangles and dots. The forewing is 16–17 mm long. The underside of the hindwing has a distinctive purplish band.
B. dia differs from the pearl-bordered fritillary in having a sharp angle to its hindwing (readily seen from underside when perched with wings closed). The similar Titania's fritillary has a less sharply-angled hindwing and only occurs at high altitude.
In Europe the larvae feed on Viola species (Viola odorata, Viola hirta, Viola canina, Viola reichenbachiana, Viola tricolor), and outside Europe on Prunella vulgaris and Rubus idaeus.


Boloria dia is found in Europe, over the Caucasus east across the Palearctic to Mongolia. It is widespread and common across southern France. In Europe it occurs from northern Spain, Italy and Greece to Poland, the Balkans and Turkey. It is not found in Britain.


The two-spotted bumble bee (Bombus bimaculatus) is a species of social bumble bee found in the eastern half of the United States and the adjacent south-eastern part of Canada. In older literature this bee is often referred to as Bremus bimaculatus, Bremus being a synonym for Bombus. The bee's common name comes from the two yellow spots on its abdomen. Unlike many of the other species of bee in the genus Bombus, B. bimaculatus is not on the decline, but instead is very stable. They are abundant pollinators that forage at a variety of plants.


Bombus bimaculatus is in the subgenus Pyrobombus, which is closely related to the subgenera Alpinobombus and Bombus out of the 15 total. Within Pyrobombus, B. bimaculatus is most closely related to B. monticola, B. sylvicola, and B. lapponicus. Additionally, B. bimaculatus can oftentimes be confused with B. impatiens and B. griseocollis, as their colorations are very similar.


Bombus bimaculatus was first described by Ezra Townsend Cresson, an American entomologist, in 1863.
Workers look very similar to queens, with the two mainly distinguished by size. Sometimes large workers can be mistaken for small queens, especially toward the end of the season when workers have grown larger and new queens emerge. Queens have a black face with a triangular patch of yellow hairs on the vertex. Their thorax is yellow except for a shining area on the disc that is bordered by black hairs. Their venter is black with some yellow hairs on the legs.
Male faces have intermixed black and yellow hairs. They resemble females in most markings, except their tergite 2 has more yellow lateral hairs than the female whose tergite 2 has black edges and few yellow lateral hairs.

The size of the radial cell in the wing differs for each. Workers have the smallest, ranging from 2.5 to 3.6 mm. Males are slightly bigger at 2.6–3.6 mm. Queens have the largest at 3.4–4.1 mm.


B. bimaculatus is mainly found in eastern temperate forest regions throughout the United States and the southeastern part of Canada. It can also live in the coastal plains of the southeastern United States, the eastern Boreal forest, and the eastern Great Plains.
This bee lives in underground nests, preferably in or around wooden areas and gardens. Nests can be anywhere from 6 inches to a foot below the surface. Tunnels traveling to the nest range from 9 inches to 4 feet long. B. bimaculatus can also nest above ground or in cavities. Bees do not build nests and instead rely on finding abandoned rodent dens, hollow logs, suitable man-made structures, or tussocks. Queens will hibernate in loose dirt or rotting logs.
This bumble bee is very common and has been experiencing steady growth unlike many other bumble bees that are in decline.


Bumble bee colonies are annual and a new colony is founded when a mated queen, the foundress, emerges from hibernation in the spring. Habitats for hibernation and colonies are different so she must find a suitable location to start her nest and she must do this on her own. She will provision it with pollen and nectar and then lay her eggs. This first brood will become non-reproducing female workers. At this time the queen must alternate between incubating the larvae and foraging for more provisions. Thus, this is the most vulnerable time for a fledgling colony. Alternatively, some queens will not have mated the previous year and her offspring will all be male.
Eggs typically hatch after four days and spend two weeks feeding on stored provisions before pupating. After another two weeks the pupae will have developed into adults. Once the workers emerge, queens will forage less and spend more time laying eggs. For B. bimaculatus, workers typically emerge in May and peak in July. Workers are responsible for brood care, foraging, regulating nest temperature and defending the nest. Males emerge last in June and peak in July. Unlike workers who stay and care for the brood, males will soon leave the nest after maturation to seek mates. New queens are produced at about the same time as males, and will forage extensively to build reserves for their overwintering. Unlike males that leave the nest and do not return, new queens will return to the nest at night.
B. bimaculatus is one of the earliest bumble bee species to emerge, with queens being sighted as early as February. By the time fall arrives, newly mated queens will all be hibernating to repeat the cycle the following spring. Workers, males, and foundresses will have died. B. bimaculatus's colonies emerge quickly and die quickly in comparison with other bumble bee species.


Male B. bimaculatus can help care for larvae during the first days, or even weeks, of their life. Though female workers are mainly responsible for brood care, males cannot fly for the first 24 hours of their life so they cannot leave the nest. Incubating larvae is a potential opportunity for males to exercise their flight muscles. They assume the same position on the cocoon as females would and pump their abdomen to facilitate heat flow from their thorax to their abdomen to the brood. Male incubation may be more significant towards the end of the season when there are fewer workers to incubate larvae.


B. bimaculatus mate outside the nest with males patrolling in circuits, searching for a queen to mate with. Most queens only mate once; however, there are some queens who mate multiple times and have offspring of multiple paternity.


B. bimaculatus queens forage on Aquilegia flowers. The queens hang upside down on stamens, clutch the filament with their forelegs, and scrape off pollen using their middle and hind legs. Workers enter the Aquilegia spurs by pushing their head and part of their thorax into the spur's mouth. They then extend the maxillae and tongue into the spur to drink nectar, repeating this process on multiple spurs of the same plant before visiting the next one.
B. bimaculatus queens' probosces range from 10.53 to 12.19 mm in length, which has little overlap with other Bombus species. This may potentially be the reason why B. bimaculatus are such abundant pollinators.
Research comparing B. bimaculatus to Xylocopa virginica, a carpenter bee, found that the former learned faster and had more flexible foraging patterns. It was hypothesized that B. bimaculatus being a social bee could have individuals specialize in either foraging for nectar or pollen, instead of having to worry about both in overall food collection as the nonsocial carpenter bees needed to do.


Bumble bees eat nectar and pollen from plants. B. bimaculatus is known to pollinate a wide variety of plants, but they seem to have favorites. Queens can be found on willow and plum. Workers are found on red clover and mint. Males are found on mint and sweet clover.
As a species they have been found foraging at the following plants:
Zenobia pulverulenta
Gelsemium sempervirens
Lyonia lucida
Solanum dulcamara
Aquilegia species
Dicentra species
Mertensia species
Pedicularis species
Aesculus glabra
Camassia scilloides
Delphinium tricorne
Hydrophyllum appendiculatum


Predators of bumble bees include crab spiders, Florida black bears, ambush bugs, robber flies, dragonflies, assassin bugs, and some wasp species. Crab spiders ambush B. bimaculatus at flowers, paralyze them, and then eat them. Florida black bears eat B. bimaculatus most abundantly in the spring, and continue to eat them to a lesser extent in the summer.


B. bimaculatus will defend its nests against intruders, such as Psithyrus variabilis, a cuckoo bumble bee. In an experiment, a female P. variabilis was placed in a B. bimaculatus nest. Workers quickly recognized her as an intruder, halted their work and attacked her when she entered the inner part of the nest.
Oftentimes though, B. bimaculatus are content to ignore intruders, such as Psithyrus labrosius. Like P. variabilis, P. labrosius also is a cuckoo bumble bee. It will attack Bombus vagans, but not B. bimaculatus though they are in the same subgenus, Pyrobombus.
B. bimaculatus queens can kill each other when dueling. Queens can also be hostile to unrelated workers of their own species by squirting feces in their faces.


Brachycoma sarcophagina is an ectoparasitoid that will consume B. bimaculatus bees from the outside. Female B. sarcophagina deposit young larvae on B. bimaculatus larvae. B. sarcophagina larvae will not begin consuming their host until the host has begun spinning its cocoon.
Tracheal mites, will parasitize multiple Bombus species, but strongly prefer B. bimaculatus. Mites were recovered from the autosomal air sacs of bumble bees. These mites can affect behavior and reduce longevity, which may cause further stress to colonies already facing difficulties.
Conopid flies also parasitize B. bimaculatus. Male bees were less likely to be parasitized than workers, and larger bees were more likely to be parasitized than smaller bees.
B. bimaculatus is also parasitized by a bumble bee of the subgenus Psithyrus, Bombus citrinus, a brood parasite.


B. bimaculatus can be infected with Nosema bombi, a microsporidian. This bee can also be infected by other fungal species. It is unknown how detrimental such an infection is to the bee's health. Compared to other bumble bees that are in decline, B. bimaculatus has a lighter infection, which may be the reason why it is experiencing stable growth compared to the decline in other Bombus species. However, the reason for the difference in infection is unknown.
B. bimaculatus can also be infected by Crithidia bombi and Apicystis bombi. Both are protozoans, but C. bombi is known to hinder colony creation, decrease host lifespan and colony fitness, and have a negative effect on workers' behavior. This can cause undue stress on colonies, leading to a species' decline.


The gut bacteria of B. bimaculatus was isolated and include Snodgrassella alvi and Gilliamella apicola strains. B. bimaculatus had more gut bacteria from environmental sources, and less core bacteria compared to other bumble bee species. B. bimaculatus had more core bacteria when collected from farms as opposed to collection from semi-natural habitats.


B. bimaculatus is an important pollinator in temperate forest regions as it is still abundant, unlike many other species of honey and bumble bees. They also pollinate a wide variety of plants. In addition, bumble bees can continue foraging even under sub-optimal conditions such as rain or clouds. B. bimaculatus is capable of flying even at 7 °C. This makes the continued growth and stability of B. bimaculatus particularly valuable.


Only female bees have a sting, males do not. Bumble bees typically only sting when defending their nest or when captured. Allergies to bumble bee stings are much less common than allergies to honey bee stings though the venom composition is similar. B. bimaculatus venom contains additional proteins, including acrosin and a tryptic amidase related to clotting enzymes.


Bombus flavifrons, the yellow-fronted bumble bee or yellowhead bumblebee, is a species of bumblebee. It is native to North America, where it is distributed across much of Canada, Alaska, and the western contiguous United States.


This is a robust bumblebee; the queen has a body length between 13 and 16 mm (0.51 and 0.63 in) and a wingspan of 27 to 34 mm (1.1 to 1.3 in), the male is 11 to 12 mm (0.43 to 0.47 in) in length with a wingspan of 25 to 26 mm (0.98 to 1.02 in), and the workers are 9 to 12 mm (0.35 to 0.47 in) in length and 19 to 27 mm (0.75 to 1.06 in) in wingspan.
The yellow-fronted bumble bee has a dense, untidy fur. The head is yellow with black hairs intermixed on the posterior part, the thorax has a mixed black and yellow colouration, often (always with the queen) with a black, central field. The first two terga (abdominal segments) are yellow, on the females often with a black, central field on terga 1 to 2. Terga 3 and 4 are red, and the tail black, sometimes with yellow fields.
Subspecies
Subspecies include:
B. f. dimidiatus — with the red fur more or less entirely replaced with black
B. f. flavifrons


The queen emerges from her hibernation at the end of March and often builds a nest in a disused mouse nest. The first workers appear about a month later. The nest declines at the end of August, and all the inhabitants die, except for the new queens, which hibernate in the earth. The bumblebee feeds on several flowering plants, most commonly those in Asteraceae, Fabaceae, Saxifragaceae, and Lamiaceae.
This species is host to the parasitic indiscriminate cuckoo bumblebee (Bombus insularis).
This bee occurs at high altitude and latitude, living in habitat such as tundra, taiga, and mountain forests and meadows.


Bombus griseocollis is a species of bumblebee known commonly as the brown-belted bumblebee. It is native to much of the United States except for the Southwest, and to the southernmost regions of several of the provinces of Canada.


The queen is 2.1 to 2.3 centimeters long and about a centimeter wide at the abdomen. Its head and face are black with scattered yellow hairs. The thorax is coated in yellow hairs. The abdomen is yellow banded with black, with a black posterior and black ventral surface. The legs are black.
Workers are smaller than the queen, sometimes less than a centimeter long. They are similar in color pattern, but may have a brown-yellow band around the abdomen.
Males are about 1.5 to 1.9 centimeters long and about 0.7 centimeters wide at the abdomen. They have very large eyes that span about two thirds the width of the head. The face and thorax have yellow hairs and the abdomen is banded with yellow, yellow-brown, and black.
Eggs are white, robust, and slightly curved. The average length is  2.91 mm with a range of 2.8-3.1 mm and the diameter range is 0.8-1.00 mm.


This bumblebee can occupy many kinds of habitat, including meadows, wetlands, agricultural fields, and urban areas, even densely populated cities. It is a common pollinator in community gardens in New York City and it has been observed near the top of the Empire State Building over 100 stories above ground level.  Bombus griseocollis has been found in British Columbia, Canada  (collected in 1919) and Manitoba, Canada (collected in 1967) and every continental United States of America state.
This bee feeds at many kinds of plants, such as milkweeds, prairie clovers, echinaceas, loosestrife, bergamot, pickerel weeds, rudbeckias, goldenrods, clovers, and vetches. The queens particularly favor legumes.
This species nests underground or on the surface. Nests are generally small colonies of fewer than 50 workers, but they aggressively defend their establishments. This is a eusocial bee, one that forms a colony that works together to rear young with labor divided amongst reproductive and non-reproductive castes. All the daily tasks in the nest are performed by worker bees of all age groups, .
Specific tasks performed by workers include secreting wax and using it to glue the nest to a substrate, using harvested material to insulate the nest, incubating pupae by wrapping their bodies around the cocoons, regurgitating food for larvae, scraping wax off of discarded pupal cases and recycling it in the construction of honey pots, buzzing when alarmed, inspecting and patrolling the nest, foraging, and feeding.
Males perform the task of inseminating queens. They perch in areas where young queens might pass, awaiting mating opportunities. They scent mark their perches using a glandular secretion containing tetradecyl acetate and butyric acid. This is likely a signal to other males rather than to females. Males of this species also help to incubate pupae, a task done only by workers in most bee species. This is accomplished by the bee wrapping itself around the cocoon and then pumping the abdomen. More than one bee (male or female) can simultaneously incubate an egg. However, males cannot raise the temperature as high as queens can, but can maintain raised temperatures.


This is a common species in much of its wide range. Unlike many bumblebees in North America, it has experienced an average decline of 0%, and in some areas its populations may be increasing. It apparently faces no serious threats.


The tree bumblebee or new garden bumblebee (Bombus hypnorum) is a species of bumblebee common in the European continent and parts of Asia. Since the start of the twenty-first century, it has spread to the United Kingdom and Iceland. These bumblebees prefer habitats that others do not, allowing them to pollinate flowers in areas that many other species do not get to.


Bombus hypnorum has a short proboscis and a rounded head. The thorax is usually of a uniformly ginger color (but examples with a darker, or even black thorax occur), the abdomen is covered in black hair, and the tail is always white. In workers, the first tergite (abdominal segment) is black-haired, but a proportion of males may have ginger hairs intermixed with the black hair, both on the face and on the first abdominal tergum. On the European continent, individuals with extended yellow coloration exist. Workers are often (but not always) small, while drones are much bigger in comparison. The queens vary in size.


Bombus hypnorum is part of the genus Bombus. Its closest genetic relatives are B. jonellus and B. sichelli.


B. hypnorum is a common bumblebee species in continental Europe and northern Asia, from northern France to Kamchatka in the east, and from the Pyrenees to the mountains in northern Europe. In the Balkans it is found in northwestern Greece. It is not found, though, in the Mediterranean, or the steppes of eastern Europe, only in the mountains of the Iberian Peninsula and not south of Tuscany in Italy. The bumblebee was first observed in United Kingdom on 17 July 2001 close to the village of Landford in Wiltshire and has since been spreading widely. In August 2008, B. hypnorum was found in Iceland, and new queens have been found each year since. It is likely that it will continue to stay in Iceland and prosper in close living with humans near dense settlements, such as Reykjavík, but will most probably not venture into the more rural and colder parts of Iceland. In the U.K., it has now spread from England up to the north of Scotland and Wales.


This bumblebee often lives near human settlements. It prefers to build its nest above ground and often inhabits bird boxes. B. hypnorum likes to live in forests, but in places where there are not as many trees, it favours human dwellings. It likes to live in holes and walls in the trees unlike other members of the Bombus species. B. hypnorum does not stay in areas where there is a high amount of rapeseed cover.


The nest is quite large, with 150 workers or more (according to some authorities up to 400). This species stores pollen in separate cells, and feeds each larva individually.  It visits an enormous range of flowering plants such as Rhododendron, cherry, grape hyacinth and, in the north, blueberry and Vaccinium. It is also an important visitor to raspberry (Rubus idaeus) and bramble (Rubus fruticosus agg.).


There have been dead queens around colonies that are established, so this may have been a result of one queen usurping another colony and keeping some of the workers of the original colony.


The tree bumblebee has a short breeding cycle. Nests are begun by single queens in March. These queens produce a brood of workers, then queens and males. The first cycle is completed from mid-May to early July (depending on the season). A smaller second generation is produced in late summer in favorable years. Larger colonies have heavier queens.


Development of larvae into a queen or a worker is determined by the amount of food that was given to them. Workers have a shorter development time than the queens. The queens have a higher amount of juvenile hormone than the workers as larvae.


Compared to Bombus terrestris, B. hypnorum has a weaker caste system in addition to a smaller overall colony. An important determinant in caste hierarchy is how much food the larva receive during its development. When they are older, they are seen to organize themselves by using the information they obtain from cues in odor pattern and arrange themselves into groups this way.


There are three worker groups in the colony. They are dominant workers, subordinate workers, and foragers. Dominant workers were aggressive towards other workers by attacking and sometimes even biting others. They can show this dominance without fighting by giving off a certain odor that is similar to the queen's.


Queens in this species can be polyandrous.  Multiple mating is not common in bumblebees. In this species it is related to short matings, possibly with little sperm transferred. Because of multiple mating, sisters in a colony may have different fathers.


There are two parts to mating: approach and copulation. First there is the approach part where the male checks out the female. The male would approach a queen and then hover in the air for a few seconds using his antennae to inspect the female. If this male is the same species, then he will land and continue inspection using his antennae.  The male mounts her by using his front legs on her abdomen and then mounts from the rear. Then he attempts to copulate with her. Females have a mandibular gland that releases a pheromone that the males react to so that they will know of their receptiveness. Males use their legs to tap on the abdomen of the female for a few seconds in ten second intervals. Males of B. hypnorum copulate for about 20-40 min.


Females in this species are unlike other species where they usually only mate once. B. hypnorum can mate 2-3 times in their lifetime; however, this is not always the case. It has been observed that a female can mate up to 6 times. When looking at the second mating, it does not seem to be shorter or longer than the first mating, but they are usually shorter than the females that have mated only once in their lifetime. This can be due to the fact that the mating plugs disappear relatively quickly, in 6–12 hours. However observed matings may not be the same as actual sperm transfer, though from this also, it is clear that multiple mating occurs in this species.


Social bees are of the order Hymenoptera. The female workers are more genetically related to each other than to their brothers because males are haploid, giving an identical set of chromosomes to their daughters.


There seems to be a hierarchy around the egg-laying workers in the nest. While the queen was alive, this bee would eat any other workers that were laying eggs in the nest. If this worker dies, the next in the hierarchy would start up this act as well and at the same time defend her own eggs.


The relatedness from sister to sister is 75% and from sister to brother is 25%. This is because females are diploid and males are unfertilized haploid.  The Queen has equal genetic relatedness to both her sons and daughters so she wants to lay an equal ratio of children. Since B. hypnorum also can mate with more than one male, then the colony has groups of related females. In these colonies, the queen has sex ratio control so the offspring are equally male and female.


They maintain a symbiotic relationship with phoretic mites, which they transport, and which probably feed on mushrooms or nest parasites.


B. hypnorum has the biggest preference for the flowering trees Crateagus monogyna and Prunus spinosa compared to other types of bumble bees.  Also compared to other bees, B. hypnorum has less of a preference for Brassica naptus, Glechoma hederacea and Lamium album.


Workers and males have similar responses to chemical stimuli; however, the males are just slightly more responsive. Queens have the highest response overall.


The tree bumblebee is generally quite docile, but if disturbed, it can defend its nest proactively and it has been known to sting people whom it perceives as a threat.


Bombus impatiens, the common eastern bumble bee, is the most commonly encountered bumblebee across much of eastern North America. They can be found in the Eastern temperate forest region of the eastern United States, southern Canada, and the eastern Great Plains. Because of their great adaptability, they can live in country, suburbs, and even urban cities. This adaptability makes them a great pollinator species, leading to an increase in their commercial use by greenhouse industry. This increase consequently led to their farther spread outside their previous distribution range. They are considered one of the most important species of pollinator bees in North America.


The generic epithet (the first part of the name) Bombus comes from the genus Bombus, which is also commonly known as bumblebee and belongs to the tribe Bombini. The specific name (the latter half of its scientific name) may come from the flowers of the genus Impatiens, which is one of its food sources. An alternative explanation is that these bees are easily provoked into stinging, and so are "impatient."
Including B. impatiens, the genus Bombus contains 250 species and most species are characterized by their eusociality or parasitic nature. Specifically, the genus Bombus has 49 subgenera, and B. impatiens belongs to the subgenus Pyrobombus. B. impatiens is also of the order Hymenoptera and family Apidae which characterizes its kin selection and relatedness.


The bees of B. impatiens are similar to those of B. bimaculatus, B. perplexus, B. vagans, B. sandersoni, and B. separatus in their appearance. They have short and even hair, medium-sized heads with cheeks that are similar in width to their heads, and a long and rectangular body. In general, queens and workers are similar in their coloring, pubescence, and structure. However, with a body length of 17–23 mm, queens have bigger bodies than males or workers. Workers have bodies that are 8.5–16 mm, and males have bodies that are 12–18 mm long. The differences in their sizes can be observed by the differences in their larval weight at second instar. In addition to the difference in their sizes, males slightly differ in their coloring. While queens and workers are both black with a yellow thorax and first abdominal segment, males have a yellow face and head.


B. impatiens have underground nests that are 1–3 feet below the ground surface. They enter their nests using tunnels that are 18 inches to 9 feet long. Unlike the nests of honeybees or paper wasps, the nests of B. impatiens do not have a predictable pattern. The bees lay egg clumps all over inside the nest instead of having one brood area around which the workers’ distribution center is arranged.
Within the nest there is a special division of labor and social organization. 11–13% of workers maintain small spatial fidelity zones inside the nest, and all workers remain at a specific distance from the colony center. Smaller individuals maintained smaller spatial zones and tended to be closer to the center of the nest. Individuals that perform the in-nest task of larval feeding were found in the center of the nest, while foragers were often found on the periphery of the nest when not foraging.


Broadly, they can be found in the Eastern temperate forest region of the eastern United States, southern Canada, and the eastern Great Plains. More specifically, its range includes Ontario, the New England States, Georgia, Mississippi, Kentucky, Tennessee, Alabama, Maryland, Delaware, New Jersey, New York, Pennsylvania, South Carolina, North Carolina, Virginia, West Virginia, south to Florida, west to Michigan, Illinois, Kansas, Missouri, and Iowa. Also, the increase in their commercial use by greenhouse industry led to the spread of the species outside its previous distribution range. Bombus impatiens adapts well to a variety of habitats, nectar sources, and climates and was seen visiting a variety and abundance of plants. In addition to agricultural, wetland, and urban conditions, the species can thrive in wooded habitats, and is likely related to woodland spring ephemerals. It nests underground in open fields and woods.


To start colonies, the gynes usually leave their hibernacula starting in mid-April and establish colonies in May. In the beginning of June, the workers start to emerge and in August and September the male bees and young queens start appearing. However, at times, the bees can emerge around late to mid-October. In terms of colony sizes, a colony of B. impatiens consists of more than 450 individual bees and most are worker bees.


A gyne mates with a male bee near the end of the hive's life cycle. They rest on the ground or on vegetation in order to mate and the mating lasts from 10 to 80 minutes. In order to increase the probability of his genes getting passed down safely, the male mates for a certain amount of time to let his sperm harden during mating.  Soon thereafter the gynes hibernate.  The following spring they emerge from hibernation and set about to get strong on nectar and to find a suitable old mouse or chipmunk hole to begin a colony.  The first thing she builds is a honeypot, then she fills it with food (nectar/pollen), making it easier to feed her new brood, which are raised in paper cells she builds.  The queens lay about 2000 eggs in one season, but only half of them will survive to become full adults.


Foragers of B. impatiens colonies use a strategy called traplining, in which the bees visit their food sources in a repeatable sequence, to improve their efficiency, especially in an unfamiliar environment. The bees establish traplines by searching among flowers in an orderly manner. Upon establishment, the traplines remain stable for long periods of time. Traplining has many advantages. The bees can minimize both the distance traveled by linking the sources in a more direct path and the time spent searching by knowing the locations of food sources. Also, the bees can travel through the locations that were recently depleted of their resources, saving their energy and time.


B. impatiens use communication in order to maximize the benefit of foraging. The bees become faster and more accurate as they become more experienced at foraging, and the returning foragers tend to stimulate the foraging activity of the colony. The foragers of B. impatiens improve their foraging activity by communicating with others in their nests. They share their abilities to associate scents of good food sources.