According to Gail Wallin, executive director of the Invasive Species Council of B.C., and co-chair of the Canadian Council on Invasive Species, by 2015 it was found in all provinces in Canada except Manitoba and Saskatchewan. In Vancouver the aggressive plant went under "four lanes of highway and have popped up on the other side." At Mission Point Park in Davis Bay, British Columbia municipal crews attempted to eradicate it by digging out the plant to a depth of about three metres with an excavator. It grew back twice as large the next year. To avoid an epidemic as in the United Kingdom, some provinces in Canada are pushing for relaxation of provincial limits on the use of herbicides close to waterways so knotweed can be aggressively managed with strong chemicals. In spite of its status as an invasive species it is still sometimes sold or swapped in Canada as an edible "false bamboo." Bohemian knotweed, a hybrid between Japanese and giant knotweed that produces huge quantities of viable seeds, now accounts for about 80 per cent of knotweed infestations in British Columbia.


Rhabdothamnus solandri is a small shrub of the family Gesneriaceae endemic to New Zealand. It is the only plant of the genus Rhabdothamnus, and the only member of Gesneriaceae native to New Zealand. Its common names are New Zealand gloxinia and, in the Māori language, taurepo, mātātā and waiū-atua.
The species is found throughout the North Island, less commonly in the southern part of the island, and its offshore islands, in a variety of locations such as forests, near streams, or on banks. It grows as a shrub up to 2 metres tall. It has distinctive trumpet-shaped flowers that are modest-sized at 2–2.5, and up to 4, centimetres long. The flowers are usually orange, but sometimes brick-red, yellow, purple or pink, and are longitudinally striped by 12–14, even up to 20, red or dark orange veins. It flowers year-round, peaking between October and February.
The flowers are pollinated mainly by the bellbird, tūī and stitchbird. The silvereye, which is a 19th-century immigrant to New Zealand that has not co-evolved with this and other native plants, has a beak too short to pollinate the flowers, but sometimes rips through the sides of the flowers to steal nectar. The local extinction of the bellbird and stitchbird in the upper North Island in around 1870, and the retreat of tūī to higher canopy and more nectar-rich exotic flowers, has caused a long-term reduction in the reproduction of the shrub, which requires pollination to produce seeds. However, as the plant is slow-growing and long-lived, its populations persist. Due to extinction debt, the future extinction of this shrub is nearly guaranteed.


Rhagium inquisitor, the ribbed pine borer, is a species of longhorn beetle in the family Cerambycidae. It was described by Carl Linnaeus in his landmark 1758 10th edition of Systema Naturae. It is distributed widely in the Holarctic, and its larvae burrow into the wood of larch, pine, spruce, birch and oak trees.


Rhagium mordax, the black-spotted longhorn beetle, is a species of long-horned beetle. This beetle is found throughout Europe and to Kazakhstan and Russia. Larvae develop in silver fir, hazel, European weeping birch, European beech, and the European chestnut. Ischnoceros rusticus is an ichneumonid parasitoid wasp that feds on Rhagium mordax larvae.


There are five formally described varieties:
Rhagium mordax var. altajense Plavilstshikov, 1915
Rhagium mordax var. klenkai Heyrovský, 1914
Rhagium mordax var. mediofasciatum Plavilstshikov, 1936
Rhagium mordax var. morvandicum Pic, 1927
Rhagium mordax var. subdilatatum Pic, 1917


Rhagonycha fulva, the common red soldier beetle, also misleadingly known as the bloodsucker beetle, and popularly known in England as the hogweed bonking beetle is a species of soldier beetle (Cantharidae).


Rhagonycha fulva was first described by Giovanni Antonio Scopoli in 1763 in Entomologia Carniolica as Cantharis fulva.


Rhagonycha fulva measures 8–10 millimetres (0.31–0.39 in) in length. Its antennae are black, occasionally the first segment is orange. The head and pronotum are orange and shiny, with fine pubescence visible on the head. The shape of the pronotum is variable, but it narrows towards the head. The elytra cover the wings and most of the abdomen and are a dark, shiny red in colour, and terminate in a clearly visible black patch on the apical end - this is one of their key identifying features. Its femora and tibiae are orange, but the tarsi are black; the third segment of the tarsi is simple rather than bilobed.
All soldier beetles are soft-bodied, resulting in the German name of this species as Roter Weichkäfer (meaning "Red, soft beetle").


This beetle is very common in Europe and Anatolia. Introduced to North America, it is well established in British Columbia and Quebec and recently recorded in Ontario.


Adults feed on aphids, and also eat pollen and nectar. Larvae prey on ground-dwelling invertebrates, such as slugs and snails, and live at the base of long grasses. The adults, which are active between the months of June and August, spend much of their short lives mating and can often be seen in pairs.


Rhagonycha fulva is commonly found on open-structured flowers and can be spotted in grassland, woodland, along hedgerows and in parks and gardens, often on flower species such as Anthriscus sylvestris (Cow Parsley) and others of the genus Heracleum (Hogweed) and the family Asteraceae during the summer. R. fulva is a significant pollinator of two species of Hogweed, Heracleum sphondylium, and H. mantegazzianum.


Rhamnus alaternus is a species of flowering plant in the buckthorn family Rhamnaceae, known by the common names Italian buckthorn or Mediterranean buckthorn. It is a hardy medium-sized evergreen shrub with fragrant flowers.


The specific Latin name alaternus, is from the Latin word for the plant. Its origin is obscure but is often suggested to be of Etruscan or pre-Indo-European Mediterranean origin.


Rhamnus alaternus is an evergreen shrub 1–5 metres (3 ft 3 in – 16 ft 5 in) high. The stems have reddish bark and  pubescent young branches, rounded and compact foliage with alternating leaves, 2–6 centimetres (0.79–2.36 in) long, sometimes nearly opposite, oval or lanceolate, leathery, shiny green, yellowish-green underneath.
The small fragrant flowers are gathered in a short axillary yellow-green raceme. The flowering period extends from February to April. Fruits are obovoidal red-brownish drupes of about 3–4 millimetres (0.12–0.16 in),  containing from 2 to 4 seeds. The drupes  darken to black when ripe.


This species is widespread in thermophilic evergreen bush and scrubland of the Mediterranean climate regions, from Gran Canaria, Morocco and Portugal in the west, to the Levant in the east, from sea level up to 1,300 m (4,300 ft) altitude.


In Australia, where it was introduced as a garden shrub, it has become a serious invasive woody weed in many areas, especially coastal parts of SE Australia. Here it displaces native shrubs of similar size such as the sea box, Alyxia buxifolia (an endemic plant which had an important medicinal role for aboriginal people). It prevents subshrubs and herbaceous ground cover native plants from surviving due the heavy shade and competition for moisture and nutrients. It can form dense thickets with very low biodiversity.


This species is cultivated as an ornamental garden shrub, valued for its glossy evergreen leaves and red berries. The variegated cultivar 'Argenteovariegata' has gained the Royal Horticultural Society's Award of Garden Merit.


Rhexia alifanus, commonly referred to as savannah meadowbeauty, is a flowering plant in the Rhexia genus. A perennial, it has pink blossoms. It is indigenous to areas of the southeastern United States west to Texas.


Walter, Thomas (1788). Flora Caroliniana, secundum Systema vegetabilium Linnæi digesta, characteres essentiales naturalesve et differentias veras exhibens; cum emendationibus numerosis, descriptionum antea evulgatarum adumbrationes stirpium plus mille continens, necnon generibus novis non paucis, speciebus plurimis novisq. ornata (in Latin). London: Sumptibus J. Fraser Prostant venales apud J. Wenman, in Vico vulgo dicto Fleet-street. p. 130. doi:10.5962/bhl.title.9458. OCLC 2428892. Retrieved 20 August 2019.
"Lady Bird Johnson Wildflower Center - The University of Texas at Austin". www.wildflower.org.
"Rhexia alifanus - Species Details". Atlas of Florida Plants.


Rhexia mariana is a species of flowering plant in the Melastomataceae family known by the common names pale meadow beauty or Maryland meadowbeauty. It is native to the eastern and lower midwestern United States.
This species is a colonial perennial herb producing stems up to 2.5 feet tall. The oppositely arranged leaves have elongated, toothed blades. The flower is 1 or 2 inches wide. It is pink, purple, or white with yellow or orange anthers. The fruit is a red urn-shaped capsule containing brownish seeds.
This species is used in landscaping and sometimes as a roadside planting.


Rhexia mariana has distinct, symmetrical flowers that can be any color from white to shades of lavender. Rhexia mariana has anthers 4–11 mm long. These anthers are often yellow or orange. Depending on the conditions in which they are grown, leaf size varies widely. Rhexia mariana has anthers 4–11 mm long.  The leaves are opposite and lanceolate to lance-oblong. Usually only one vein is visible per leaf, but they actually each have three. Rhexia mariana var. exalbida, sometimes only has one vein per leaf. Leaf edges are serrate, with hairs present. The stem of Rhexia mariana is square and pubescent.


Rhexia mariana  was first described by Linnaeus in Species Plantarum in 1753. Rhexia mariana has 8 subspecies, including Rhexia mariana var. portoricensis , Rhexia mariana var. exalbida, and Rhexia mariana var. interior. This plant is one of 5115 known species in the Melastomataceae family. Rhexia mariana has a few common names, including the Pale Meadow Beauty or the Maryland Meadow Beauty.


Rhexia mariana can be found in marshy, wet areas, with full sun. It prefers a moist soil that is either loamy or sandy. The Rhexia mariana var. exalbida can be found in drier soils than other variants, making it one of the more aggressively spreading varieties. Rhexia mariana prefers acidic soil, with a pH of 6 or lower. While it does not do well in the shade, Rhexia mariana is a great wildflower for beginner gardeners with full sun and moist, acidic soils. This North American wildflower can be found from New York all the way south to Florida and west to Texas.


The species Rhexia mariana is not considered threatened or endangered globally. The global rank is G5 (secure), but it is threatened in some states. In Maryland, Rhexia mariana ranges from imperiled to critically imperiled, depending on the area of the state. In Massachusetts, the only New England state in which the plant still occurs, Rhexia mariana is considered endangered.


Rhexia mariana often grows in locations that are under human developmental pressure, such as lake and pond-side. This means that as development occurs, the amount of habitat for the species is shrinking. In areas like Cape Cod MA, USA, where human populations have seen steady growth since the 1825, many plant species, including many Rhexia mariana populations have been extirpated.


Occasional flooding is important for Rhexia mariana to thrive along pond and lake shores. The occasional flood keeps the shore line uninhabitable for upland species, reducing competition for Rhexia mariana and other wetland plants. However, the water level must fluctuate, receding back for periods of time, in order for aquatic species not to take hold and outgrow Rhexia mariana. Human water consumption has depleted the water table in some places, disrupting regular fluctuation patterns.


In order for Rhexia mariana seeds to germinate they must be exposed to light. They germinate in the 20/35C temperature regime in the New England states. Additionally, Rhexia mariana seeds were found to be the only seeds from the Melastomataceae family in the temperate region to experience physiological dormancy. In only a square meter worth of ground covered in Rhexia mariana there is the potential for over 900,000 seeds to grow and disperse.


Rhexia mariana is a common weed in many blueberry fields in North Carolina. Flumioxazin, an herbicide, has been found to be quite effective in killing Rhexia mariana, without harming crops such as blueberries. Rhexia mariana has roots that grow in the same soil zone as blueberries, making them an important target for weed control in these agricultural fields.


Rhexia mariana can be host to species such as the corn earworm (Heliothis zea) and the tobacco budworm (Heliothis virescens).


Rhexia virginica, the handsome Harry or Virginia meadow-beauty, is a species of flowering plant in the family Melastomataceae. It is native to much of eastern North America, and is often found in moist, often acidic soils in open areas.
This species is a perennial herb that is easily identified by its distinctly angled stems. It produces purple-pink flowers in the summer that use buzz pollination for reproduction.


Rhinanthus alectorolophus, the European yellow-rattle, is a plant species of the genus Rhinanthus, native to Europe.


Rhinella horribilis is the scientific name used for populations of the cane toad or giant toad located in Mesoamerica and north-western South America when they are considered to be a separate species from Rhinella marina, a name which is then mostly restricted to Amazon basin populations. R. horribilis was originally described from Mexico as Bufo horribilis before later being considered a synonym of Bufo marina and later Rhinella marina. The specific epithet horribilis has now been revived after a 2016 study argued that these populations in fact make up two separate species.


The long-nosed snake (Rhinocheilus lecontei) is a species of nonvenomous snake in the family Colubridae. The species is endemic to North America. It has two recognized subspecies.  The other species in the genus were previously considered subspecies.


The long-nosed snake is distinguished by a long, slightly upturned snout, which is the origin of its common name. It is tricolor, vaguely resembling a coral snake with black and red saddling that almost looks like banding, on a yellow or cream-colored background, which can look somewhat like yellow banding. Cream-colored spots within the black saddles are a distinct characteristic of the long-nosed snake. It differs from all other harmless snakes in the United States by having undivided subcaudal scales. The total length (including tail) of adults is usually 22–32 in (56–81 cm), but the maximum record total length is 41 in (100 cm).


R. lecontei is a shy, nocturnal burrowing snake. It spends most of its time buried underground.


The long-nosed snake feeds on lizards, amphibians, and sometimes smaller snakes and infrequently rodents.


R. lecontei is oviparous, laying clutches of 4-9 eggs in the early summer, which hatch in the late summer or early fall.


The long-nosed snake is not apt to bite, but will release a foul smelling musk and blood from the cloaca as a defense mechanism if harassed.


The preferred natural habitats of the long-nosed snake are desert, grassland, shrubland, and savanna.


Western long-nosed snake, Rhinocheilus lecontei lecontei Baird & Girard, 1853
Texas long-nosed snake, Rhinocheilus lecontei tessellatus Garman, 1883


The long-nosed snake is not often found in the exotic pet trade as it frequently rejects rodent-based diets that are most readily available for captive snakes.


Rhionaeschna californica, the California darner, is a species of darner in the dragonfly family Aeshnidae. It is found in Central America and North America.
The IUCN conservation status of Rhionaeschna californica is "LC", least concern, with no immediate threat to the species' survival. The population is stable. The IUCN status was reviewed in 2017.


The blue-eyed darner (Rhionaeschna multicolor, syn. Aeshna multicolor) is a common dragonfly of the family Aeshnidae; native to the western United States, it is commonly sighted in the sagebrush steppe of the Snake River Plain, occurring east to the Midwest from central Canada and the Dakotas south to west Texas and Oklahoma. In Central America it occurs south to Panama. This is usually the second earliest darner to emerge in the spring, with the California darner emerging first. It hunts small flying insects while on the wing.


The blue-eyed darner is a large species with a length of 65–70 mm (2.6–2.8 in). The eyes of both males and females are bright blue. The male is dark brown to brownish black. The top of the thorax, behind the head, is marked with two blue stripes, and each side of the thorax is marked with a pair of blue diagonal stripes. The abdomen is marked with both large and small blue spots. The anal appendages of males and females are forked and the female is marked similarly to the male; however, the base color is brown and the markings are green.


Rhionaeschna mutata, the spatterdock darner, is a species of darner in the dragonfly family Aeshnidae. It is found in North America.
The IUCN conservation status of Rhionaeschna mutata is "LC", least concern, with no immediate threat to the species' survival. The population is stable. The IUCN status was reviewed in 2017.


The grey fantail (Rhipidura albiscapa) is a small insectivorous bird. There is no sexual dimorphism. It is a common fantail found in Australia, the Solomon Islands, Vanuatu and New Caledonia. The species is considered by many to be conspecific with the New Zealand fantail (Rhipidura fuliginosa); however, differences in its calls lead some authorities to treat it as a separate species. The studies of grey fantail in 1999 by Richard Schodde and Ian Mason recommended that Tasmanian grey fantail was formally classified as R. albiscapa and New Zealand fantails populations as R. fuliginosa


Numerous birds of southern Australia are characterised by a known biogeographical barrier, the Nullarbor Plain, displaying morphological divergence of subspecies differentiation. Because of the east-west division due to the geographic barrier effect on their morphological divergence, the populations of R. albiscapa could be classified into five subspecies by their characteristics, such as their calls, patterns of plumage, and nest construction.
Five subpopulations of R. albiscapa are shown below:
Rhipidura albiscapa keasti (eastern Australia)
Rhipidura albiscapa albicauda (western Australia)
Rhipidura albiscapa preissi (western Australia)
Rhipidura albiscapa alisteri (eastern Australia)
Rhipidura albiscapa albiscapa (Tasmania)


Most bird species typically build one nest, whereas grey fantails commonly build more than one nest before egg-laying, and seven nests have been recorded as the highest number in a breeding season. In a recent study, there is a hypothesis explaining nest abandonment in this species. Abandoned nests could be used for confusing predators. In fact, a large number of abandoned nests exposed on trees are significantly less concealed than nests that eventually received eggs. However, these abandoned nests were incompletely built, probably in response to the attention of predators (such as pied currawongs), because these predators may destroy incomplete nests when looking for eggs. In addition, pied currawongs are larger than grey fantails, which presents a considerable risk for adult grey fantails. Therefore, desertion might be an adaptation of grey fantails, with these nests used for eliminating hazards from cryptic predation. Some of the materials from decoy nests could be used to construct the subsequent breeding nest. The location of the breeding nest varies during the nest-building phase, ensuring a site with sufficient security to prepare for breeding. The parent birds build compact, cup-shaped nests, usually in the forks of trees, made from moss, bark and fibre, and often completed with spider's web. According to the records of the sizes of the nests by Richard and Donaghey, which were observed in three regions of southern Australia, the average size of nests were 5.7 cm (5.1-6.4 cm) external diameter, 4.1 cm (3.8-4.4 cm) internal diameter, and 2.9 cm (2.5-3.2 cm) internal depth.


The grey fantail is territorial and it is a seasonal breeder.  They raise several broods per season, usually each of three or four cream eggs, spotted grey and brown. The incubation period is around two weeks, with incubation and feeding duties shared by both parents. During the breeding season, the mass of testes of male grey fantails grows larger than in the non-breeding season. The growth of testes sizes could be subject to sperm competition, similar to other species exhibiting morphological traits. Male birds also have pronounced cloacal protuberances. This change of morphology is associated with polygynandry and the increase in copulation chance. Despite most grey fantails forming season-long monogamous pairs, a small number of male birds seeking extra-pair copulation have been recorded. To seek extra-pair copulation, the male bird invades neighbouring territories and waits at the nest where the female birds were not incubating. The intruding male might coerce a resident female into accepting extra-pair male copulation. Moreover, the aggression of the male bird could act as a deterrent to the female bird, leading to delayed ovulation, allowing the male to re-mate. This increases the likelihood of the male becoming the sole fertiliser of that female's eggs.


Rhizomnium glabrescens, also called fan moss or large leafy moss, is a species of moss in the genus Rhizomnium.


The plants are upright, unbranched and unisexual. Their stems are naked, up to 3 cm high, are shiny and have large leaves. Male plants have large, rose-like clusters of leaves at the tip. Female plants have capsules. It is very common on rotting logs, humus and soil over rocks in low- and middle-elevation forests. Indeed, it is the most common species of leafy moss in low-elevation forests.


Rhizophora mangle, the red mangrove, is distributed in estuarine ecosystems throughout the tropics. Its viviparous "seeds", in actuality called propagules, become fully mature plants before dropping off the parent tree. These are dispersed by water until eventually embedding in the shallows.
Rhizophora mangle grows on aerial prop roots, which arch above the water level, giving stands of this tree the characteristic "mangrove" appearance. It is a valuable plant in Florida, Louisiana, and Texas coastal ecosystems.  In its native habitat it is threatened by invasive species such as the Brazilian pepper tree (Schinus terebinthifolius).  The red mangrove itself is considered an invasive species in some locations, such as Hawaii, where it forms dense, monospecific thickets. R. mangle thickets, however, provide nesting and hunting habitat for a diverse array of organisms, including fish, birds, and crocodiles.


Red mangroves are found in subtropical and tropical areas in both hemispheres, extending to near 28°N to S latitude. They thrive on coastlines in brackish water and in swampy salt marshes. Because they are well adapted to salt water, they thrive where many other plants fail and create their own ecosystems, the mangals. Red mangroves are often found near white mangroves (Laguncularia racemosa), black mangroves (Avicennia germinans), and buttonwood (Conocarpus erectus) though often more seaward than the other species. Through stabilization of their surroundings, mangroves create a community for other plants and animals (such as  mangrove crabs). Though rooted in soil, mangrove roots are often submerged in water for several hours or on a permanent basis. The roots are usually sunk in a sand or clay base, which allows for some protection from the waves.
Specimens of Moesziomyces aphidis have been collected from water samples and on Rhizophora mangle leaves along the Perequê-Áçu River, in mangroves located in São Paulo State, Brazil.


Red mangroves are easily distinguishable through their unique prop roots system and viviparous seeds. The prop roots of a red mangrove suspend it over the water, thereby giving it extra support and protection. They also help the tree to combat hypoxia by allowing it a direct intake of oxygen through its root structure.
A mangrove can reach up to 80 ft (24 m) in height in ideal conditions, but it is commonly found at a more modest 20 ft (6.1 m). Its bark is thick and a grey-brown color. Mangrove leaves are 1–2 in (2.5–5.1 cm) wide and 3–5 in (7.6–12.7 cm) long, with smooth margins and an elliptical shape. They are a darker shade of green on the tops than on the bottoms. The tree produces yellow flowers in the spring.


As a viviparous plant, R. mangle creates a propagule that is in reality a living tree. Though resembling an elongated seed pod, the fully grown propagule on the mangrove is capable of rooting and producing a new tree. The trees are hermaphrodites, capable of self or wind pollination. The tree undergoes no dormant stage as a seed, but rather progresses to a live plant before leaving its parent tree. A mangrove propagule may float in brackish water for over a year before rooting.


Rhodobaenus quinquepunctatus, the cocklebur weevil, is a species of snout or bark beetle in the family Curculionidae. It is found in North America.


Rhododendron canescens, the piedmont azalea or mountain azalea, is a pink-blooming azalea native to the Eastern United States.


Rhododendron ferrugineum, the alpenrose, snow-rose, or rusty-leaved alpenrose is an evergreen shrub that grows just above the tree line in the Alps, Pyrenees, Jura and northern Apennines, on acid soils. It is the type species for the genus Rhododendron. It may grow up to 1.5 m (4.9 ft) tall and produces clusters of pinkish-red, bell-shaped flowers throughout the summer. The undersides of the leaves are covered in rust-brown spots, which give the species the second part of its binomial name (ferrugineum, Latin for 'rust-coloured, ferruginous'). This is in contrast to Rhododendron hirsutum, which has no such brown colouring, has hairy edges to the leaves and grows over limestone. Where the two species co-occur (usually on soils of intermediate pH), the hybrid Rhododendron × intermedium may occur; as its name suggests, it is intermediate in form between the two parental species.
Rhododendron ferrugineum is moderately toxic, containing arbutin, arecoline and rhodoxanthin, and can cause vomiting, and difficulties of the digestive, nervous, respiratory and circulatory systems.


Rhododendron macrophyllum, the Pacific rhododendron, California rosebay, California rhododendron, coast rhododendron or big leaf rhododendron, is a large-leaved species of Rhododendron native to the Pacific Coast of North America. It is the state flower of Washington.


It is an evergreen shrub growing up to 2–9 m (7–30 ft) tall. The leaves, retained for 2–3 years, are 7–23 cm (3–9 in) long and 3–7 cm (1–3 in) broad. The flowers are 2.8–4 cm (1.1–1.6 in) long, with five lobes on the corolla; color is usually pink, although variants exist.


The northern limit of its range is somewhat north of the border between Canada and the United States in British Columbia. It is found as far south as Monterey Bay in California. It is widely distributed in the Coast Mountains and Cascade Range. It is less abundant in the coastal mountains of Washington and northern Oregon and more common south of the Siuslaw River. It is mostly coastal in distribution but extends its range eastward to locations in the Cascade Mountains in Oregon, Washington and British Columbia.


Rhododendron macrophyllum, like many rhododendrons, thrives in disturbed habitats such as roadside embankments and recently deforested wildlands. They can also live up in the mountains. It also grows in coastal and montane conifer woods.


Archibald Menzies found R. macrophyllum growing along with Arbutus menziesii in May 1792 when he and George Vancouver made their second landfall after leaving Hawaii, near present-day Port Discovery, Washington. Seed was sent to England in 1850 by William Lobb.
In recent years it has been the main focus of a study group at the Rhododendron Species Foundation in Federal Way, Washington, the Western North American Rhododendron Species Project. The WNARSP is documenting the detailed range and forms of all of the western North American rhododendron species.


The species contains andromedotoxin, which can poison the honey of nearby hives.


Rhododendron maximum — its common names include great laurel, great rhododendron, rosebay rhododendron, American rhododendron and big rhododendron — is a species of Rhododendron native to the Appalachians of eastern North America, from Alabama north to coastal Nova Scotia.


Rhododendron maximum is an evergreen shrub growing to 4 m (13 ft), rarely 10 m (33 ft), tall. The leaves are 9–19 cm (3.5–7.5 in) long and 2–4 cm (0.79–1.57 in) broad. The flowers are 2.5–3 cm (0.98–1.18 in) diameter, white, pink or pale purple, often with small greenish-yellow spots. The fruit is a dry capsule 15–20 mm (0.59–0.79 in) long, containing numerous small seeds. The leaves can be poisonous. Leaves are sclerophyllous, simple, alternate, and oblong (10 to 30 cm long, 5 to 8 cm wide). It retains its waxy, deep-green leaves for up to 8 years, but once shed are slow to decompose. It produces large, showy, white to purple flowers each June and July.


Approximately 12,000 square miles in the southern Appalachians are occupied by this species where it dominates the understory. This species has historically been confined to riparian areas and other mesic sites but takes advantage of disturbed areas where it is present to advance onto sub-mesic sites. It prefers deep well-drained acid soils high in organic matter where it produces a thick, peat-like humus. It prefers low to medium light conditions for optimum carbon gain, and has a tremendous capacity for avoiding cavitation during freeze-thaw cycles.  Where extensive overstory mortality has eliminated most of the overstory, this species forms a thick and continuous subcanopy known locally as ‘laurel slicks’ or ‘laurel hells’. Rosebay rhododendron is an important structural and functional component of southern Appalachian forest ecosystems. What isn't clear is whether or not we are in a period of advancement or retreat for this species. For example, on poorly drained sites on ridge or upper slope positions, large areas of rosebay rhododendron, particularly at the high elevations, have recently died out presumably due to the Phytophthora fungus, or due to recent prolonged periods of below-average precipitation. Yet, rosebay rhododendron now occupies sites that historically were free of evergreen understory. There are still important questions to be answered regarding this species to completely understand its role in forest understories.


Rosebay rhododendron is clonal. It is capable, however, of reproducing both vegetatively and sexually. It reproduces vegetatively through a process called ‘layering’ where it produces roots from above ground woody parts when in contact with the forest floor. The fruit is produced from showy flowers from March to August. The fruit is an oblong capsule that ripens in the fall, and splits along the sides soon after ripening to release large numbers of minute seed (approx. 400 per capsule).  Microsite requirements for seed germination are relatively specific (e.g., high in organic matter such as rotting logs); hence, the majority of reproduction is vegetative resulting in a clonal distribution.


Seeds from rosebay rhododendron are minute and it is estimated that approximately 11 million are contained in 1 kg. Commercial seed production is generally from cultivated hybrids. Seeds from wild sources are not commonly sold commercially. Rosebay rhododendron is a slow-growing shrub and has a very high sprout potential. If mechanical removal is attempted in the case of forest management, extremely high densities are attained by this species in a matter of a few years. Prescribed fire has also been used to control this species but with limited success.


Rosebay rhododendron is a striking and aesthetically pleasing feature of mesic southern Appalachian forests. It is one of the largest and hardiest rhododendrons grown commercially. Several cultivars with white to purple flowers have been selected for the horticultural trade.  Where it occurs naturally, it produces a showy, white, pink, or light purple flower primarily in June, but occurs from March into August. Rosebay rhododendron maintains deep-green foliage year round. This species affords protection to steep watersheds and shelter for wildlife. The wood is very hard and is occasionally used for specialty wood products.


For all its prized qualities as a naturally occurring component of the landscape or as plantings in residential and commercial landscaping, rosebay rhododendron can have an inhibitory effect on regeneration of other plant species. There is some evidence to suggest that due to fire suppression and the absence of other cultural activities (i.e., mountain-land grazing), this species has advanced beyond the mesic forest sites into sub-mesic understories. The significance of this movement onto previously unoccupied sites centers around the impacts of rosebay rhododendron on plant succession and resource availability.  Rosebay rhododendron is associated with reduced woody and herbaceous seedling abundance throughout its range, and hence poses a serious impediment to the production of wood products. The mechanism(s) by which rosebay rhododendron reduces seedling survival has been the subject of much debate. Possible sources of inhibition include allelopathy, competition for resources including light, physical and chemical attributes of the forest floor and soil, and interactions between some or all sources.


Rhododendron maximum is the state flower of the U.S. state of West Virginia.


Rhododendron menziesii, also classified as Menziesia ferruginea, is a species of flowering plant in the heath family Ericaceae, known by several common names, including rusty menziesia, false huckleberry, fool's huckleberry and mock azalea.


Rhododendron menziesii is a mostly erect or spreading shrub often exceeding 3 metres (9.8 ft) in height, and reaching lower heights at higher elevations.
Its branches are coated in thin, scaly, shreddy bark and its twigs with fine glandular hairs.
The alternately arranged deciduous leaves are oval in shape with pointed tips, reaching 4 to 6 centimeters long. The leaves are hairy, glandular, and sticky in texture, and have an unpleasant skunklike odor when crushed.
The inflorescence is a loose cluster of hanging bell- or cup-shaped flowers in shades of pink to orange to yellow-green. The flower has 4 to 5 petals which are mostly fused into a cylinder, and eight stamens inside. The bloom period is June and July.
The fruit is a valved capsule under a centimeter long which contains many seeds.


The shrub is native to northwestern North America from Alaska through the Pacific Northwest to northwestern California and Wyoming.
It is a member of the flora in mountain forests. It grows in the understory of subalpine fir (Abies lasiocarpa), Pacific silver fir (A. amabilis), Coast redwood (Sequoia sempervirens), western redcedar (Thuja plicata), western hemlock (Tsuga heterophylla), and other conifers.
The plant prefers cold, wet, densely vegetated habitats where it can grow in deep shade.


Rhododendron periclymenoides, the pink azalea or pinxter flower, is a species of shrub in the heath family Ericaceae. It is native to eastern North America, where it is widespread from Alabama to New Hampshire. It is often found in riparian areas, in wet to dry forests.
This species produces showy pink flowers in the spring. They have 2-inch (51 mm) long stamens; they  carry a strong, sweet scent similar to petunias. The leaves are bright green and ovate. The trunk grows to be about 9 feet (2.7 m) tall. Like many members of the genus, the plant contains toxins in all parts of the flower.


Rhododendron periclymenoides occurs throughout the Eastern United States, from southern New York south to Georgia, with isolated populations in Midwestern states. This plant prefers habitats in swamp margins, moist woods and open areas with full to partial sunlight or high, open shade. Soils in which Rhododendron periclymenoides grows best are typically acidic, rich in humus and retain moisture but should still have some drainage. Common ecosystems in which this plant can be found are oak-hickory, oak-pine- spruce-fir, maple-beech-birch and white- ed-jack pine. Common pollinators of R. periclymenoides are hummingbirds and butterflies.


About 860 species belong to the genus Rhododendron. Rhododendron periclymenoides was first described by Michaux. A synonym of R. periclymenoides is R. nudiflorum but was synonymized in 1962 by Shinners.


One of the common names of R. periclymenoides is the “pinxterbloom azalea”. “Pinxter” is Dutch for the word Pentecost, a name used for the seventh Sunday after Easter. This is typically around the time when the flowers bloom.


Rhododendron periclymenoides has low levels of toxicity, and all parts of the plant may cause vomiting or diarrhoea if ingested in quantity. The poisons produced by rhododendrons are known as grayanotoxins, which are a class of neurotoxins. These neurotoxins work by blocking the inactivation of sodium channel receptors, causing cell dysfunction.
The honey which is made by bees which collect pollen from genus Rhododendron species is referred to as “mad honey”. Humans who ingest this honey begin exhibiting many of the symptoms listed above as well as hypotension and other irregularities of cardiac rhythm. Outside of “mad honey” ingestion, human poisoning by rhododendrons is rare. However, pets and other livestock can still ingest the plant parts. While not common in the United States, “mad honey” is believed to have medicinal qualities in China.


Rhododendron periclymenoides is susceptible to problems caused by both insects and disease. Common insects which cause damage to R. periclymenoides are aphids, nematodes, borers, lace bug, mites and whitefly. Common diseases include crown and root rot, leaf spot and powdery mildew. Many of the wild R. periclymenoides have more resistance to these issues than the hybrids which are bred for gardens.


Rhododendron periclymenoides is used in horticulture as an ornamental plant. Common landscape uses for the plant are as a foundation plant? and in shrub borders. Both seeds and cuttings of the plant can be used for propagation. Since lack of proper drainage can lead to root rot, North Carolina State University advises the use of raised beds if the plant is going to be grown in soil that contains a lot of clay.


Many animals and birds utilize shrubs like R. periclymenoides for cover on the forest floor. The roots also provide erosion control and protection for watersheds.


According to the United States Forest Service, wildfires typically “top kill” azaleas. After wildfires have come through an area, R. periclymeniodes can resprout from subsurface structures.


Rhodotypos scandens, the sole species of the genus Rhodotypos, is a deciduous shrub in the family Rosaceae, closely related to Kerria and included in that genus by some botanists. It is native to China, Korea, possibly also Japan.


It grows to 2–5 m tall, with (unusually for a species in the Rosaceae) opposite (not alternate) leaves, simple ovate-acute, 3–6 cm long and 2–4 cm broad with a serrated margin. The flowers are white, 3–4 cm diameter, and (also unusually) have four (not five) petals; flowering is from late spring to mid-summer. The fruit is a cluster of 1-4 shiny black drupes 5–8 mm diameter.
It does not have a widely used English name, most commonly being known by its genus name rhodotypos, also occasionally as jetbead or jet-bead. It is an invasive species in some parts of eastern North America.


"Rhodotypos scandens". Natural Resources Conservation Service PLANTS Database. USDA. Retrieved 21 October 2015.
Flora of China


Rhopalomyia californica, the coyote brush bud gall midge, is a species of gall midges, insects in the family Cecidomyiidae.


Rhopalomyia solidaginis, the goldenrod bunch gall, is a species of gall midges, insects in the family Cecidomyiidae.


The nīkau palm is the only palm species endemic to mainland New Zealand. Its natural range is coastal and lowland forest on the North Island, and on the South Island as far south as Okarito (43°20′S) in the west and Banks Peninsula (43°5′S) in the east.  It also occurs on Chatham Island and Pitt Island/Rangiauria to the south-east of New Zealand, where it is the world's southernmost palm at 44° 18'S latitude.
Nīkau grow up to 15 m tall, with a stout, green trunk which bears grey-green leaf scars. The trunk is topped by a smooth, bulging crownshaft up to 1 m long. The fronds are up to 3 m long, and the closely set, sometimes overlapping leaflets are up to 1m long. The inflorescence is multibranched and from 20 to 40 cm long. The tightly packed flowers are unisexual and coloured lilac to pink. Male flowers are borne in pairs, and have six stamens. The female flowers are solitary. The fruit is elliptic or oblong, and generally measures about 10 by 7 mm, and is red when ripe. Nīkau produce flowers between November and April, and fruit ripens from February to November, taking almost a year to fully ripen. These are a preferred food of the kererū (native pigeon).


Nīkau make an excellent potted plant, and are quite hardy. They tend to be slow-growing. They grow readily from seed if the fruit is soaked in water for a few days and then gently scrubbed to remove the flesh. The seed will then germinate readily if placed in sealed plastic bags in partial shade, after which they can be planted in deep pots. The pots should be tall and narrow to provide room for the taproot and to lessen the likelihood of root damage when transplanting.
Transplanting juveniles is generally successful if the main root is left intact. Nīkau do not have a true tap root. Once the main root has been established to a fairly shallow depth of about 400 mm, roots take on form consistent with other palms. Successful transplanting is possible, but nīkau are very fickle if any trunk is present. It is best done in summer, but a substantial root ball should be preserved, and shade should be provided at the new location – at the very least by tying the outer fronds closer to the centre. Ground watering is recommended because crown watering can induce terminal rot at the very slow-growing new spike. Delays should be avoided in getting nīkau into new ground, and substantial die-back of all but the central spike can be expected.
Nīkau thrive on cool temperatures, but are not subject to freezing weather in their natural habitat. They can survive a few degrees of frost, but are damaged even more severely by sudden large drops in temperature even above freezing. Nīkau grow well in areas with a mild Mediterranean climate.


The nīkau palm shows considerable variation in the wild. Plants from the South Island and the offshore islands of the North Island have larger, more-gracefully-arching fronds and are popular in cultivation. The Chatham Islands form is particularly different, having a distinct juvenile form and larger fruits, and a thicker covering of fine hairs on the fronds. More research is needed into its precise relationship with the mainland form. The New Zealand nīkau palm is very similar to Rhopalostylis baueri of the Kermadecs and Norfolk Island, which can be distinguished by its more rounded or oval fruits, and by its leaflets which are broader than those found in most populations of R. sapida.


"Protoform: NII-KAU [CE] Coconut frond". Polynesian Lexicon Project Online. Retrieved 22 September 2019.
Esler, A. E. 'The Nikau Palm', New Zealand's Nature Heritage, Vol.2 Part 19 p.532, 1974
Mckendry, Lisa (2020). "Maori archaeological textiles: a structural analysis of Maori raranga 'woven' basketry from the Waitakere Ranges in Auckland Museum". Records of the Auckland Institute and Museum. 55: 19–28. doi:10.32912/ram.2020.55.2. ISSN 0067-0464. Retrieved 19 April 2021.


Rhus aromatica, the fragrant sumac, is a deciduous shrub in the family Anacardiaceae native to North America. It is found in southern Canada (Alberta to Quebec) and nearly all of the lower 48 states except peninsular Florida.
Fragrant sumac is a woody plant with a rounded form that grows to around 2 ft (0.6 m) to 5 ft (1.5 m) tall and 5 ft (1.5 m) to 10 ft (3.0 m) wide. The plant develops yellow flowers in clusters on short lateral shoots in March through May. The flower is a small, dense inflorescence that usually opens before the plant's leaves do.
The species is polygamodioecious (mostly dioecious, primarily bearing flowers of only one sex, but with either a few flowers of the opposite sex or a few bisexual flowers on the same plant). Male (staminate) flowers develop in yellowish catkins, while female (pistillate) flowers develop in short bright yellow panicles at the ends of branches.
Pollinated flowers develop clusters of 5 mm (0.2 in) to 7 mm (0.3 in) hairy red drupes containing a single nutlet during June through August. The fruits become an important winter food for birds and small mammals that can remain on the plant until spring if not eaten.
The plant's alternate compound leaves have three leaflets that vary in shape, lobing, and margination.  The unstalked leaflets are ovate to rhomboid, more or less wedge-shaped at the base, coarsely-toothed and usually shiny glabrous above. The terminal leaflet is 3 cm (1.2 in) to 6.5 cm (2.6 in) long.
Fragrant sumac's three-leafleted lobed leaves resemble those of its relative, poison ivy (Toxicodendron radicans). However, poison ivy's central leaflet has a stem, whereas fragrant sumac's does not.
The plant's  green to glossy blue-green summer foliage becomes orange to red or purple in the fall. Stems are thin and brownish-gray, with rust-colored lenticels when young. Leaves and stems emit a lemon scent when crushed. There are no terminal buds, but overwintering male catkins are present.
Fragrant sumac is common along the forested eastern margins of the Great Plains and in open or otherwise disturbed sites on the margins of the Gulf Coast prairie. It grows at a range of sites including open rocky woodlands, valley bottoms, lower rocky slopes, and roadsides. It is not widely used for landscape plantings but is often used as a ground cover, especially on banks. The plant's colorful fall foliage is its main ornamental feature.
The plant grows in full deep shade to full sun and well-drained soils slightly acid to well alkaline with a pH range of about 6.0 to 8.5. It has a shallow, fibrous root system and is easily transplanted. Some of its branches can trail upon the ground and develop roots.  The plant can ground sucker to form a colony.


It is listed as of special concern and believed extirpated in Connecticut. However, this status applies only to native populations.  In Washington, Connecticut, and New Hampshire it is considered introduced.


Shining sumac is often cultivated, where it is well-suited to natural and informal landscapes because it has underground runners which spread to provide dense, shrubby cover for birds and wildlife. This species is valued for ornamental planting because of its lustrous dark green foliage which turns a brilliant orange-red in fall. The fall color display is frequently enjoyed along interstate highways, as the plant readily colonizes these and other disturbed sites. The tiny, greenish-yellow flowers, borne in compact, terminal panicles, are followed by showy red clusters of berries which persist into the winter and attract wildlife.
The flowers are yellow, flowering in the summer.  The fruit attracts birds with no significant litter problem, is persistent on the tree and showy.
The bark is thin and easily damaged from mechanical impact; branches droop as the tree grows, and will require pruning for vehicular or pedestrian clearance beneath the canopy; routinely grown with, or trainable to be grown with, multiple trunks.  The tree wants to grow with several trunks but can be trained to grow with a single trunk.  It has no thorns.


The tree can be planted in a container or above-ground planter. It has been recommended for buffer strips around parking lots or for median strip plantings in the highway, and for land reclamation. Rhus copallinum can tolerate exposure to salt spray in maritime forests and coastal grasslands; it can grow in serpentine soil and shallow, rocky soil.
The tree grows in full sun or part shade. Soil tolerances include clay, loam, sand, slightly alkaline, acidic, and well-drained soil. Its drought tolerance is high.
The somewhat sour berrylike fruits are edible and rich in vitamin A. They are eaten by wildlife and can be made into a lemonade-like drink. Additionally, deer browse the twigs of the species. The leaves make up part of the diets of captive Coquerel's sifakas (lemurs).


Rhus integrifolia, also known as lemonade sumac, lemonade berry, or lemonadeberry, is a shrub to small tree. It is native to the Transverse and Peninsular Ranges and the South Coast regions of  Southern California. This extends from Santa Barbara County and the Channel Islands to San Diego County and extending into north-central Pacific coastal Baja California and its offshore islands such as Cedros Island.
It is 1–8 metres (3.3–26.2 ft) in height, with a sprawling form, and is a member of the chaparral plant community often found in canyons and on north-facing slopes below elevations of 900 metres (3,000 ft).  Rhus integrifolia often hybridizes with Rhus ovata.


Rhus integrifolia leaves are simple (unusual in a genus where most species are trifoliate), alternating, evergreen and leathery, ranging from two to four centimeters wide on reddish twigs; length of leaves is five to seven centimeters. Leaves are toothed with a waxy smooth appearance above and a paler tone below.  The flowers which appear from February to May are small, clustered closely together, and may be either bisexual or pistillate.
These fragrant flowers exhibit radial symmetry with five green sepals, five white to rosy-pink petals, and five stamens. The small flowers are only six millimeters across.  The ovary is superior and usually has a single ovule; although in pistillate flowers, the stamens are small and infertile. The mature fruit of Rhus integrifolia is sticky, reddish, covered with hairs, and about seven to ten millimeters in diameter.  The elliptical fruit presents tight clusters at the very ends of twigs.
Young plants manifest smooth reddish bark, while more mature individuals have cracked, even scaly, grayish bark with the smooth red bark displayed underneath.  Twigs are rather stout and flexible, and reddish bud ends are diminutive and pointed. There is often a multi-furcate branching structure from the base of the plant.  A mature plant is large and thicket-like with a sprawling arrangement.


The lemonade berry plant is found on north and east-facing slopes and canyon floors in coastal areas of southern California and northern Baja California; however, one colony has even been observed as far north as Santa Cruz County. The lemonade berry occurs in both chaparral and coastal sage scrub communities.
This plant thrives on well-drained soils and endures heat and windy conditions well. The species tolerates sandy as well as medium loam soils, and it can even thrive in nutrient deficient soil. This plant tolerates mildly acid to mildly alkaline soils, and is common on north and east-facing slopes with where shady, moist conditions are prevalent. Propagation is by seed or by rhizome. Bird species enjoy the fruits and act as a major disperser.
Lemonade berry is not frost tolerant, but will hybridize with the frost tolerant Rhus ovata (sugarbush) in the foothills of California and Mexico where their ranges overlap.


Many plants within this genus are considered toxic, although some reports indicate the berries of this species can be used to make lemonade flavored drinks (hence its common name).  Allergic reactions may also result from skin contact with sap from some of the genera.
Lemonade berry leaves are rich in tannins.  Even though the species is evergreen, there is some leaf fall in autumn, at which time the fallen leaves may be used as a brown dye or mordant.  An oil can be extracted from lemonade berry seeds; moreover, this oil achieves a tallow consistency when left to stand.  Thereafter the oil can be employed to manufacture candles, which burn brightly, albeit emitting  a pungent scent.  The wood of mature plants is dense and hard, making it prized for wood-burning fireplace kindling.


Rhus integrifolia can also be used as a landscape shrub and is suitable for hedging and espalier. The plant is vulnerable to frost, but often the plant will regrow by summer, after it appears to have died from cold. The growth habit is slow to moderate and, as a garden plant, this species is quite resistant to deer, and supplies nectar and fruit for birds and nectar for butterflies. Its cultural requirements mimic its natural environment with ample drainage and little summer water.


The specific epithet typhina is explained in Carl Linnaeus and Ericus Torner's description of the plant with the phrase "Ramis hirtis uti typhi cervini", meaning "the branches are rough like antlers in velvet".
In both French and German, the common name of the species (sumac vinaigrier; Essigbaum) means "vinegar tree".


Rhus typhina is a dioecious, deciduous shrub or small tree growing up to 5 m (16 ft) tall by 6 m (20 ft) broad. It has alternate, pinnately compound leaves 25–55 cm (10–22 in) long, each with 9–31 serrate leaflets 6–11 cm (2+1⁄4–4+1⁄4 in) long. Leaf petioles and stems are densely covered in rust-colored hairs. The velvety texture and the forking pattern of the branches, reminiscent of antlers, have led to the common name "stag's horn sumac". Staghorn sumac grows as female or male clones.
Small, greenish-white through yellowish flowers occur in dense terminal panicles, and small, green through reddish drupes occur in dense infructescences. Flowers occur from May through July and fruit ripens from June through September in this species’ native range. Infructescences are 10–20 cm (4–8 in) long and 4–6 cm (1+1⁄2–2+1⁄4 in) broad at their bases. Fall foliage is brilliant shades of red, orange and yellow. Fruit can remain on plants from late summer through spring. It is eaten by many birds in winter.
Staghorn sumac spreads by seeds and rhizomes and forms clones often with the older shoots in the center and younger shoots around central older ones. Large clones can grow from ortets in several years.
Within Anacardiaceae, staghorn sumac is not closely related to poison sumac (Toxicodendron vernix), even though they share the name "sumac".
In late summer some shoots have galls on leaf undersides, caused by the sumac leaf gall aphid, Melaphis rhois. The galls are not markedly harmful to the tree.


Staghorn sumac is an ornamental plant which provides interest throughout the year; though its vigorous, suckering habit makes it unsuitable for smaller gardens. It can grow under a wide array of conditions, but is most often found in dry and poor soil on which other plants cannot survive. Some landscapers remove all but the top branches to create a "crown" effect in order to resemble a small palm tree. Numerous cultivars have been developed for garden use, of which the following have gained the Royal Horticultural Society’s Award of Garden Merit:
Rhus typhina 'Dissecta' (cutleaf staghorn sumac)
Rhus typhina Radiance = 'Sinrus'


Rhus virens is a species of flowering plant in the mango family, Anacardiaceae, that is native to Arizona, southern New Mexico, and Texas in the United States as well as northern and central Mexico as far south as Oaxaca.
It is commonly known as the evergreen sumac or tobacco sumac.


Rhus virens var. choriophylla (Wooton & Standl.) L.D.Benson – Mearns' sumac
Rhus virens var. virens


The palm weevil Rhynchophorus ferrugineus is one of two species of snout beetle known as the red palm weevil, Asian palm weevil or sago palm weevil. The adult beetles are relatively large, ranging between 2 and 4 centimetres (1 and 1+1⁄2 inches) long, and are usually a rusty red colour—but many colour variants exist and have often been classified as different species (e.g., Rhynchophorus vulneratus). Weevil larvae can excavate holes in the trunks of palm trees up to 1 metre (3.3 ft) long, thereby weakening and eventually killing the host plant. As a result, the weevil is considered a major pest in palm plantations, including the coconut palm, date palm and oil palm.
Originally from tropical Asia, the red palm weevil has spread to Africa and Europe, reaching the Mediterranean in the 1980s. It was first recorded in Spain in 1994, and in France in 2006. Additional infestations have been located in Malta, Italy (Tuscany, Sicily, Campania, Sardinia, Lazio, Marche, Puglia and Liguria), Croatia and Montenegro. It is also well established throughout most of Portugal, especially in the South. It also has established in Morocco, Tunisia, and other North African countries. The weevil was first reported in the Americas on Curaçao in January 2009 and sighted the same year in Aruba. It was reported in the United States at Laguna Beach, California late in 2010 but this was a misidentification of the closely related species, Rhynchophorus vulneratus, and it did not become established.
Larvae of Rhynchophorus ferrugineus are considered a delicacy in Southeast Asian cuisine. In some regions, however, larvae farming is strictly prohibited to prevent the potential devastation of plantation crops.


Primarily due to the existence of numerous color forms across their ranges, the taxonomy and classification of red palm weevils has undergone a number of changes in understanding and circumscription. As such, the information in the literature should be viewed as a compilation of data which may apply to both species, depending primarily upon the biogeography; accordingly, the vast majority of publications presumably do refer to R. ferrugineus rather than vulneratus, as the former is by far the most widely invasive. The most recent genus-level revision in 1966 recognized two species of red palm weevil, ferrugineus and vulneratus, and for decades these were interpreted as separate taxa. A genetic study in 2004 concluded that vulneratus was not distinct from ferrugineus, and treated them as synonyms, a view that was accepted until 2013, when yet another genetic study came to the opposite conclusion, based on more comprehensive geographic sampling. Accordingly, the "red palm weevil" species that appeared in the US was vulneratus rather than ferrugineus, though the latter is the invading species in all of the other global introductions.


The native range of this species is considered to include Bangladesh, Cambodia, China, India, Japan, Laos, Pakistan, Philippines, Sri Lanka, Taiwan, and Vietnam; records from Indonesia, Malaysia, Myanmar, Singapore, and Thailand largely or exclusively refer to R. vulneratus. R. ferrugineus has now been reported and confirmed from Albania, Algeria, Aruba, Bahrain, Bosnia and Herzegovina, Croatia, Curaçao, Cyprus, Egypt, France (incl. Corsica), Greece, Israel, Italy (incl. Sicily and Sardinia), Jordan, Kuwait, Libya, Malta, Monaco, Montenegro, Morocco, Oman, Palestine, Portugal (incl. Madeira), Qatar, Saudi Arabia, Slovenia, Spain (incl. the Balearic and Canary islands), Syria, Tunisia, Turkey, and United Arab Emirates. Records from Australia, Papua New Guinea, Samoa, the Solomon Islands, and Vanuatu have not been confirmed and are likely to be specimens of Rhynchophorus bilineatus, a closely related species indigenous to the region.


absent from Algeria
Djibouti
Egypt
Libya
Mauritania
Morocco
Tunisia
Nigeria


Albania
absent from Austria
absent from Belgium
Bosnia and Herzegovina
Bulgaria
Croatia
Cyprus
absent from Denmark
absent from Finland
France
Corsica
Greece
Crete
Italy
Sardinia
Sicily
Malta
Montenegro
absent from the Netherlands
absent from Poland
Portugal
Madeira
Russia
Southern Russia
eradicated from Slovenia
Spain
Balearic Islands
eradicated from the Canary Islands
absent from Ukraine
absent from the United Kingdom
absent from England


Aruba
Curaçao
Netherlands Antilles
eradicated from the United States
eradicated from California


Australia unassessed
absent from New South Wales
absent from the Northern Territory
Queensland unassessed
absent from South Australia
absent from Tasmania
absent from Victoria
absent from Western Australia
absent from Papua New Guinea
Samoa unassessed
Solomon Islands unassessed
Vanuatu unassessed


This species of red palm weevil is reported to attack 19 palm species and is the worst such pest in the world. Although the weevil was first reported on coconut in Southeast Asia, it has gained a foothold on date palm over the last two decades in several Middle Eastern countries, and then expanded its range to Africa and Europe. This expansion has been due to the movement of infested planting material from contaminated to uninfected areas. In the Mediterranean region, the red palm weevil also severely damages Phoenix canariensis. Currently, the pest is reported in almost 15% of the global coconut-growing countries and in nearly 50% of the date palm-growing countries.
The list of known hosts includes: Areca catechu, Arenga pinnata, Borassus flabellifer, Caryota cumingii, C. maxima, Cocos nucifera (coconut palm), Corypha gebanga, C. elata, Elaeis guineensis, Livistona decipiens, Metroxylon sagu, Oreodoxa regia, Phoenix canariensis, P. dactylifera (date palm), P. sylvestris, Sabal umbraculifera, Trachycarpus fortunei, Washingtonia spp. Lab studies have reared the insect on diets of Agave americana and Saccharum officinarum, but these findings have not been observed in the wild. There is evidence that the weevil prefers the 'Sukkary' cultivar of date palm to other cultivars.
The palm species Washingtonia filifera and Chamaerops humilis may be resistant to the red palm weevil.
All known hosts of R. ferrugineus as compiled from sources by CABI ISC are: Agave americana, Areca catechu, Arenga pinnata, Borassus flabellifer, Brahea armata, Brahea edulis, Butia capitata, Calamus merrillii, Caryota cumingii, Caryota maxima, Caryota urens, Chamaerops humilis, Cocos nucifera, Corypha umbraculifera, Corypha utan, Elaeis guineensis, Howea forsteriana, Jubaea chilensis, Livistona chinensis, L. decora, Metroxylon sagu, Phoenix canariensis, P. dactylifera, P. sylvestris, Roystonea regia, Sabal palmetto, Saccharum officinarum, Trachycarpus fortunei, Washingtonia filifera, and W. robusta.


This weevil usually infests palms younger than twenty years. While the adult causes some damage through feeding, it is the burrowing of the larva into the heart of the palm that can cause the greatest mortality of trees. The adult female lays approximately two hundred eggs on new growth in the crown of the palm, at the base of young leaves, or in open lesions on the plant. The egg hatches into a white, legless larva. The larva will feed on the soft fibres and terminal buds, tunneling through the internal tissue of the tree for about a month. The larvae can occasionally grow to a length of 6 to 7 centimetres (2+1⁄2 to 3 in). At pupation, the larva will leave the tree and form a cocoon built of dry palm fibers in leaf litter at the base of the tree. The total life cycle takes about 3-4 months.


The neonate larvae are yellow-white, segmented, legless, and have a chitinous head capsule that is a darker brown than the rest of the body. They have powerful horizontal conical jaws which they use to burrow from the axils of the leaves to the crown, where they feed voraciously. Upon completion of larval development, the larva will sometimes emerge from the trunk of the tree, and build a pupal case of fiber extracted from the galleries inside the palm. The larva will then undergo metamorphosis into an adult. The larva will also weave a pupal case at the base of the palm fronds within the frond itself or at the centre of the base of the plant.


The adult insect is an excellent flier and is able to travel great distances. While they prefer to attack palms that are already infested or weakened by other stresses, they will colonize healthy palms.


R. ferrugineus is predated by Chelisoches morio, infected by a cytoplasmic polyhedrosis virus and Metarhizium pingshaense, and parasitized by Heterorhabditis indicus, Hypoaspis spp., Praecocilenchus ferruginophorus, Scolia erratica, Steinernema carpocapsae, and Steinernema riobravis.


The behaviour and bionomics of the red palm weevil have been investigated in the field. The biology and life history of the weevil have been investigated on five diets, including banana, sugarcane, squash fruit, apple, and palm crown. The rate of development showed great variation depending on the host used. Developmental time was shortest on palm crown, followed by banana, and then squash fruit and apple, and longest on sugarcane. Egg production was the highest on palm crown, being 338 ± 37.24 eggs/female followed by banana, squash fruit, and apple, and the lowest (117. ± 18.9 eggs/female) on sugarcane.
Studies show that this insect is attracted by ethyl acetate, 2-methoxy.4.vinylphenol, gamma-nonanoic lactone, 4SSS-ferrugineol, 50H and 4me-9-5Kt.


The infestation of the pest can result in yellowing and wilting of palms, that may lead to the death of the affected plant.
The crown wilts first, and lower leaves will follow, due to damage to vascular tissue. Major symptoms such as crown loss or leaf wilt are usually only visible long after the palm has become infested. Secondary infections of opportunistic bacteria and fungi may occur within damaged tissues, accelerating decline. By the time these external symptoms are observed, the damage is usually sufficient to kill the tree, and the infestation may have been present for six months or longer. In high-density infestations, sounds of the larvae burrowing and chewing can be heard by placing one's ear to the trunk of the palm. Recent research has been conducted using electronic listening devices or dogs trained to recognize the scent of weevils or palm decay to detect infestations at low densities earlier in the process.


The main control method is through the application of a systemic insecticide. Insecticide is usually applied through a funnel about 5 centimetres (2 in) above the infested area of the trunk. The red palm weevil can be monitored using pheromone lures and alternative forms of control use field sanitation and mass trapping with traps baited with pheromone and plant derived semiochemicals. New alternative technologies using semiochemicals and bioinsecticides are being developed to attract the weevils to a point source and kill them. Another management technique is to drench the base of palm fronds with the entomopathogenic fungus Metarhizium anisopliae, or Beauveria bassiana. An Italian company claims to have developed a microwave collar that can be used to sterilize individual trees. For early detection, bioacoustic analysis may be implemented by inserting a sensitive microphone into the tree and recording any produced sounds. These sounds are analyzed by digital signal processing and artificial intelligence to decide whether they are generated by palm weevils.


The larval grub is considered a delicacy in Vietnam. In Vietnam, the larvae are usually eaten alive with fish sauce. Other methods of cooking include toasting and steaming. They are eaten with sticky rice and salad or cooked with porridge. The larvae are known in the Vietnamese language as đuông dừa ("coconut beetle-larva"). "Sago worms" reported from other countries (e.g., Malaysia, New Guinea) refer to different, related species of Rhynchophorus.


European Commission - Directorate-General for Health & Consumers (2011) The insect killing our palm trees. EU efforts to stop the Red Palm Weevil. ISBN 978-92-79-21268-0
CISR: Red Palm Weevil Information
Red Palm Weevil Home
Red Palm Weevil Control & Tips
Red Palm Weevil Research Chair, King Saud University, Riyadh
Greek webpage dedicated to management
USDA information page


Rhynchospora colorata, also known as starrush whitetop, white star sedge and white-topped sedge, is a perennial sedge with white bracts, giving it the appearance of white petals with long, green points. It is native to southeastern North America, from Virginia west to New Mexico in the United States, and south into the Caribbean islands.
The inflorescence is a dense cluster of small spikes, each containing several tiny flowers. It sits on top of 3–10 green and white bracts that grow to 10–15 cm long. These bracts look much like leaves, but the actual leaves arise from the base of the plant.


Rhyothemis graphiptera, known as the graphic flutterer or banded flutterer, is a species of dragonfly of the family Libellulidae.
It is found across northern Australia, the Moluccas, New Guinea and New Caledonia. Rhyothemis extends from Africa to the western Pacific.
The flight of the genus Rhyothemis is usually fluttering. Rhyothemis graphiptera, a medium-sized dragonfly (wingspan 70mm, length 35mm), inhabits lagoons, lakes, ponds and swamps. The abdomen is dark and the wings are brownish-yellow with dark mottled markings.
The taxon has been assessed for the IUCN Red List as being of least concern, and is noted in the Catalog of Life.


Rhyparochromus vulgaris is a species of dirt-colored seed bug in the family Rhyparochromidae. It is found in Africa, Europe and Northern Asia (excluding China), North America, and Southern Asia. This bug was first recorded in North America in 2001.
Rhyparochromus vulgaris is sometimes considered a member of the genus Raglius, Raglius vulgaris.


Ribes americanum is a shrub growing 0.5 to 1.5 meters (20-60 inches) in height. The branches are erect and bear deciduous leaves. There are no spines. The plant may form thickets. The glandular leaves are up to 7–8 cm (3–3 in) long and have 3 or 5 lobes. They turn red and gold in the fall.
The inflorescence is a spreading or drooping raceme of up to 15 flowers. Each flower has reflexed white or greenish sepals a few millimeters long and smaller whitish petals. The fruit is a smooth rounded black berry about a centimeter (0.4 inch) wide and edible when cooked. The plant reproduces mostly by seed.


This shrub is native to the United States and Canada where grows in a variety of ecosystems. It occurs in many types of forests and in conifer bogs. In Manitoba it can be found in marshes. In the Great Lakes region it grows abundantly in sedge meadows (Carex spp.). Ribes americanum grows on plains and in mountains and sometimes in disturbed areas such as roadsides. It is also shade-tolerant, growing in the understory of closed-canopy woodlands and forests.
It has also been introduced to northern China.


Several bee species visit the flowers: Augochlora pura, Augochlorella aurata, Ceratina calcarata, Ceratina dupla, and Ceratina strenua.
This plant is an alternate host for the white pine blister rust (Cronartium ribicola), the vector of a pine tree disease. It is sometimes eradicated in attempts to control the rust.
The cluster cup rust (Puccinia caricina) forms aecia on the leaves of Ribes americanum in the spring, later developing brown blotches of pustules. The telia are formed on sedges (Carex).


Native Americans made pemmican from the berries, which are also known for being made into jam and jelly.


Ribes bracteosum, the stink currant, is a species of currant native to western coastal North America from southeastern Alaska to Mendocino County in California.
R. bracteosum is a deciduous shrub, without thorns, growing to 3 metres (10 feet) tall. The leaves are 5–20 centimetres (2–8 inches) across, palmately lobed with 5 or 7 lobes. The flowers are produced in spring after the leaves emerge, on racemes 15–30 cm (6–12 in) long containing 20–40 flowers; each flower is 5–10 millimetres (3⁄16–3⁄8 inch) in diameter, with five white or greenish-tinged petals. The fruit, born in clusters, is dark blue with a whitish bloom, edible but sometimes unpleasant.


Ribes cereum is a species of currant known by the common names wax currant and squaw currant; the pedicellare variety is known as whisky currant. The species is native to western North America.


Ribes cereum is a spreading or erect shrub growing between 20 centimetres (8 inches) and 2 metres (6+1⁄2 feet) in height. The stems are fuzzy, often very glandular, and lack spines and prickles. The gray-green leaves are somewhat rounded and divided into shallow lobes which are toothed along the edges. The leaves are hairless to quite hairy and usually studded with visible resin glands, particularly around the edges. The inflorescence is a clustered raceme of 2 to 9 flowers. The small flower is tubular with the white to pink sepals curling open at the tips to form a corolla-like structure. Inside there are minute white or pinkish petals, five stamens, and two protruding green styles. The fruit is a rather tasteless orange-red berry up to 1 cm (3⁄8 in) wide, with a characteristically long, dried flower remnant at the end.
The plant is aromatic, with a spicy scent. The hairs on much of the plant can contribute to a carrion-like odor.


The species is native to western North America, including British Columbia, Alberta, and much of the western United States, from Washington, Oregon, and California to as far east as the western Dakotas and the Oklahoma Panhandle.
It grows in several types of habitat, including mountain forests in alpine climates, sagebrush, and woodlands. It can grow in many types of soils, including sandy soils and soil made of clay substrates, serpentine soils, and lava beds.


The berries are a significant food source for deer and are consumed by other animals.


Some Native American tribes ate the berries. The Zuni people eat the berries of the pedicellare variety, as well as the leaves with uncooked mutton fat or deer fat. One field guide reports that the berries are somewhat toxic and can have an unpleasant flavor. Eating too many may cause a burning feeling in the throat. One source says they are good when ripe, and can be made into jam or pie fillings.


Ribes cynosbati is a North American species of shrub in the family Grossulariaceae (gooseberries and currants). It is native to the eastern and central United States and Canada. It has several common names, including prickly gooseberry, eastern prickly gooseberry, dogberry, and dog bramble. It grows in rich forests, rocky slopes, and open heaths from New Brunswick south along the Appalachian Mountains to northern Alabama and west as far as Manitoba, the Dakotas and Oklahoma.


Ribes cynosbati reaches a height of up to 1.5 m (4 ft 11 in) with erect to spreading stems. The leaves have 3 or 5 lobes, with glandular hairs. The flowers are greenish-white. The round fruits are bristly, white to greenish, and pleasant-tasting.


Ribes indecorum is an erect perennial shrub approaching three meters in maximum height. The stem is fuzzy and glandular in texture. The deciduous leaves are 1 to 4 centimeters long. The thick, wrinkly blades are divided into three to five toothed lobes, and are hairy, glandular, and aromatic. The inflorescence is a loose raceme of 10 to 25 flowers. The flower is roughly tubular with the white or pink-tinged sepals spreading open to reveal smaller whitish petals inside. The fruit is a hairy, sticky purple berry under a centimeter wide.


This Ribes species, Ribes indecorum, is another that is cultivated as an ornamental plant by specialty plant nurseries. It is planted in drought-tolerant, native plant, and wildlife gardens and natural landscaping projects.


The shrub Ribes lacustre is known by the common names prickly currant, black swamp gooseberry, and black gooseberry. It is widely distributed, from California to Alaska and across North America east to Pennsylvania and Newfoundland, and south as far as New Mexico.
The shrub grows erect to spreading, 0.5–2 m. Clusters of reddish to maroon flowers bloom in spring. The fruit consists of dark purple berries 6–8 mm long. It blooms in April through August and may be found in low-elevation forests to the subalpine.
Outside its native range, Ribes species may be invasive.


Ribes malvaceum, the chaparral currant, is a member of the Grossulariaceae (gooseberry family). It is native to California and northern Baja California, where it occurs from sea level to 1,500 metres (4,900 ft), in chaparral, foothill oak woodland, and closed-cone pine forest habitats.


Ribes malvaceum typically grows 5–10 feet (1.5–3.0 m) tall. This perennial shrub lacks the characteristic nodal spines which are demonstrated on the stems of many other members in the genus Ribes.  The leaf blades (20–50 mm) are densely hairy, glandular, and double toothed.
Inflorescences are 10-25 flowered and open, occurring October to April in native range.  The hypanthium (5–8 mm) is pink and about twice as long as it is wide.  The sepals are pink-purple in color and are 4–6 mm.  Petals are 2–3 mm and can range in color from pink shades to white.  The flower also contains two fused styles which are fused to the tip and have a hairy base.
Striking glaucous purple berries are produced. The (6–7 mm fruit is glandular and covered by white hairs.


There are several varieties of R. malvaceum:
Ribes malvaceum var. clementinum — (Dunkle)
Ribes malvaceum var. malvaceum — plants with dark green leaves occurring below 800 metres (2,600 ft).
Ribes malvaceum var. viridifolium — (Abrams) — plants with bright green leaves occurring up to 1,500 metres (4,900 ft)


Ribes malvaceum is cultivated as an ornamental plant by specialty plant nurseries. It is used in traditional gardens, native plant landscapes, and as bird food source in habitat gardens. It thrives under oaks in bright dry conditions, and in many other locations.
Pollination ecologists have reported the plant important as a honey plant for attracting large numbers of native bees.


The blackcurrant (Ribes nigrum), also known as black currant or cassis, is a deciduous shrub in the family Grossulariaceae grown for its edible berries. It is native to temperate parts of central and northern Europe and northern Asia, where it prefers damp fertile soils. It is widely cultivated both commercially and domestically.
It is winter hardy, but cold weather at flowering time during the spring may reduce the size of the crop. Bunches of small, glossy black fruit develop along the stems in the summer and can be harvested by hand or by machine. Breeding is common in Scotland, Poland, Lithuania, Latvia, Norway, and New Zealand to produce fruit with better eating qualities and bushes with greater hardiness and disease resistance.
The raw fruit is particularly rich in vitamin C and polyphenols. Blackcurrants can be eaten raw but are usually cooked in sweet or savoury dishes. They are used to make jams, preserves, and syrups and are grown commercially for the juice market. The fruit is also used to make alcoholic beverages and dyes.


Ribes nigrum, the blackcurrant, is a medium-sized shrub, growing to 1.5 by 1.5 metres (5 by 5 ft). The leaves are alternate, simple, 3 to 5 cm (1+1⁄4 to 2 in) broad and long with five palmate lobes and a serrated margin. All parts of the plant are strongly aromatic. The flowers are produced in racemes known as "strigs" up to 8 cm (3 in) long containing ten to twenty flowers, each about 8 mm (3⁄8 in) in diameter. Each flower has a hairy calyx with yellow glands, the five lobes of which are longer than the inconspicuous petals. There are five stamens surrounding the stigma and style and two fused carpels. The flowers open in succession from the base of the strig and are mostly insect pollinated, but some pollen is distributed by the wind. A pollen grain landing on a stigma will germinate and send a slender pollen tube down the style to the ovule. In warm weather this takes about 48 hours but in cold weather it may take a week, and by that time, the ovule may have passed the stage where it is receptive. If fewer than about 35 ovules are fertilised, the fruit may not be able to develop and will fall prematurely. Frost can damage both unopened and open flowers when the temperature falls below −1.9 °C (28.6 °F). The flowers at the base of the strig are more protected by the foliage and are less likely to be damaged.
In midsummer the strigs of green fruit ripen to edible berries, very dark purple in colour, almost black, with glossy skins and calyxes at the apex (the calyxes being persistent), each containing many seeds. An established bush can produce about 4.5 kilograms (10 lb) of fruit each year.
Plants from Northern Asia are sometimes distinguished as a separate variety, Ribes nigrum var. sibiricum, of which Ribes cyathiforme is considered a synonym.


Blackcurrants can grow well on sandy or heavy loams, or forest soils, as long as their nutrient requirements are met. They prefer damp, fertile but not waterlogged ground and are intolerant of drought. Although the bushes are winter hardy, frosts during the flowering period may adversely affect the yield and cold winds may restrict the number of flying insects visiting and pollinating the flowers. A pH of about 6 is ideal for blackcurrants and the ground can be limed if the soil is too acidic. Planting is usually done in the autumn or winter to allow the plants to become established before growth starts in the spring, but container-grown stock can be planted at any time of year.
Two-year-old bushes are usually planted but strong one-year-old stock can also be used. Planting certified stock avoids the risk of introducing viruses. On a garden scale the plants can be set at intervals of 1.5 to 1.8 metres (4 ft 11 in to 5 ft 11 in) or they can be set in rows with planting intervals of 1.2 metres (3 ft 11 in) and row separations of 2.5 metres (8 ft 2 in) or more. In the UK, young bushes are generally planted deeper than their initial growing level to encourage new stems to grow from the base.


The blackcurrant requires a number of essential nutrients to be present to enable it to thrive; nitrogen provides strong plant growth and stimulates the production of flower sprigs; phosphorus aids growth, the setting of fruit and crop yield; potassium promotes growth of individual shoots and increases the weight of individual fruits; magnesium is a constituent of chlorophyll and helps increase yields through interaction with potassium; calcium is required for cell division and enlargement and is particularly important for young plants and buds.
An annual spring mulch of well rotted manure is ideal and poultry manure can also be used but needs prior composting with straw or other waste vegetable material. Spent mushroom compost can be used but care should be taken as it often contains lime and blackcurrants prefer slightly acidic soils. The blackcurrant is a gross feeder and benefits from additional nitrogen, and phosphatic and potash fertilisers should also be applied annually. A balanced artificial fertilizer can be used and a 10-10-10 granular product can be spread around the bushes at the rate of 100 to 240 g (3+1⁄2 to 8+1⁄2 oz) per plant. Weed growth can be suppressed with an organic mulch such as sawdust, bark, mushroom compost or straw, heavy plastic topped with an organic mulch cover or landscape fabric.


Blackcurrant fruit is borne primarily on one-year-old shoots. Newly planted bushes should be pruned severely, cutting all shoots back to two buds above ground level. This gives the plant a chance to get properly established before needing to put its energy into producing fruit. The general rule when pruning is to remove all weak shoots and those growing out sideways which may get weighed down when fruiting. The remaining branches should be thinned to remove old unproductive wood and to encourage new shoots. An established bush should not be allowed to become overcrowded and should have about one third of its main branches or stems removed each year. When harvesting by machine, plants with an upright growth habit are encouraged.


On a garden scale, the berries should be picked when dry and ripe. Commercially, most harvesting is done mechanically by straddle harvesters. These move continually down the rows, straddling a row of bushes, shaking the branches and stripping off the fruit. The blackcurrants are placed into half tonne bins and to minimise stoppage time, some machines have cross conveyors which direct the fruit into continuously moving trailers in the adjoining row. A modern machine can pick up to fifty tonnes of blackcurrants in a day using only one operator and two tractor drivers. The bins should be stored in a cool place. Some fruit is still picked by hand for use in the fresh fruit market.


Ribes plants are susceptible to several diseases and a number of insect pests. However, new varieties have been or are being developed to overcome some of these problems.
Reversion is a serious disease transmitted by the blackcurrant gall mite Cecidophyopsis ribis. It causes a decline in yield and is quite widespread in Europe but is rarely encountered on other continents. Symptoms include a modification of leaf shape in summer and swollen buds ("big bud") in winter, each housing thousands of microscopic mites. As pest control has limited effectiveness, severely infected bushes should be destroyed. All new plants purchased should be certified as virus-free.
White pine blister rust (Cronartium ribicola) needs two alternate hosts to complete its life cycle. One host is plants in the genus Ribes. On the blackcurrant, it causes the leaves to become pale and later develop tiny orange pustules and sometimes a yellow filamentous coating on some leaves. The fruit crop is little affected but the leaves fall early and growth is slowed the following year. The other host is any of the white pines, in which it causes serious disease and mortality for the North American species that have not co-evolved with the rust. As a result, the blackcurrant was banned in the United States as a disease vector for much of the 20th century, and even after the federal ban was lifted in 1966, several U.S. states continued their own bans, some of which remain in force as of August, 2021. The effectiveness of these restrictions is questionable, since other Ribes species also host the disease, some are native to North America, and others such as red currants and Ribes uva-crispa were never banned.
American gooseberry mildew and powdery mildew can infect the leaves and shoot tips, and botrytis may cause the fruit to rot in a wet season. Currant and gooseberry leaf spot (Drepanopeziza ribis) is another disease of blackcurrants, but it is not usually a serious problem as most cultivars now have some resistance.
The blackcurrant leaf midge can cause browning, crimping and distortion of leaves at the tips of shoots but it is seldom a serious problem. The blackcurrant sawfly (Nematus ribesii) lays its eggs on the underside of the leaves and the voracious larvae work their way along the shoots, stripping off leaf after leaf. In a serious attack, the bush can be denuded of leaves. Larvae of the currant borer drill their way along the centres of shoots, which wilt and die back. Other insect pests include scale insects, aphids and earwigs.


There are many cultivars of blackcurrant. 'Baldwin' was the mainstay of the industry for many years but it has now largely been superseded by more productive and disease-resistant varieties. During the 20th century in Europe, much hybridisation work has been carried out in order to reduce the plant's susceptibility to disease and frost and also to increase yields. This effort centered mainly in Scotland, Poland, and New Zealand.
In Britain the Scottish Crop Research Institute was tasked with developing new varieties suitable for growing in the north of the country. They produced new cultivars that had greater cold tolerance, especially in the spring, ripened earlier and more evenly and had greater fungal disease resistance. Frost tolerance was improved by selecting for late flowering and genetic research identified genes involved in resistance to gall mite and the blackcurrant reversion virus. 'Ben Lomond' was the first of the 'Ben' varieties and was released in 1975. This was followed by several other cultivars for the juicing industry such as 'Ben Alder' and 'Ben Tirran'. The cultivar 'Ben Hope' was released in 1998 with increased tolerance to gall mite, and in the same year, 'Ben Gairn' became available. It shows resistance to the reversion virus. For gardeners and the pick-your-own market, 'Ben Sarek', 'Ben Connan' and 'Big Ben' were introduced and have large, sweet berries. The cultivars 'Ben Connan' and 'Big Ben' have gained the Royal Horticultural Society's Award of Garden Merit. and new varieties are being developed continually to improve frost tolerance, disease resistance, machine harvesting, fruit quality, nutritional content and fruit flavour.
Varieties producing green fruit, less strongly-flavoured and sweeter than typical blackcurrants, are cultivated in Finland, where they are called "greencurrants" (viherherukka). In Poland, the Research Institute of Horticulture has done work on improving the blackcurrant with regard to disease and pest resistance, fruit quality, adaptations to local conditions and mechanical harvesting. Researchers have crossed various varieties and introduced inter-specific genetic material from the gooseberry (Ribes grossularia), the red currant (Ribes rubrum) and the flowering currant (Ribes sanguineum). The resulting offspring were further back-crossed to R. nigrum. Cultivars produced include 'Tisel' and 'Tiben' in 2000 and 'Ores', 'Ruben' and 'Tines' in 2005. Further cultivars 'Polares' and 'Tihope' are being tested. Since 1991, New Zealand has become an important centre for research and development, as its temperate climate is particularly suitable for cultivation of the crop. Breeding programmes are concentrating on yield, large fruit size, consistency of cropping and upright habit.
In North America, there is a need for this fruit to have resistance to white pine blister rust. New cultivars such as 'Crusader', 'Coronet' and 'Consort' have been developed there by crossing R. nigrum with R. ussuriense and these show resistance to the disease. However the quality and yield of these varieties are poor as compared to non-resistant strains and only Consort is reliably self-fertile. Back-crossing these varieties to a parent have produced new strains such as 'Titania' that have a higher yield, better disease resistance, are more tolerant of adverse weather conditions and are suitable for machine harvesting. Two new releases from a black currant breeding program in British Columbia, Canada, 'Blackcomb' and 'Tahsis', were selected for their immunity to white pine blister rust and their frost tolerance.


The blackcurrant is native to northern Europe and Asia. Cultivation in Europe is thought to have started around the last decades of the 17th century. Decoction of the leaves, bark or roots was also used as a traditional remedy.
During World War II, most fruits rich in vitamin C, such as oranges, became difficult to obtain in the United Kingdom. Since blackcurrant berries are a rich source of the vitamin, and blackcurrant plants are suitable for growing in the UK climate, the British Government encouraged their cultivation and soon the yield of the nation's crop increased significantly. From 1942 onwards, blackcurrant syrup was distributed free of charge to children under the age of two. This may have given rise to the lasting popularity of blackcurrant as a flavouring in Britain. In Britain the commercial crop is completely mechanised and about 1,400 hectares of the fruit are grown, mostly under contract to the juicing industry. Commercially, most large-scale cultivation of blackcurrants is done in eastern Europe for the juice and juice concentrate market. As of 2017, major cultivation efforts to improve fruit characteristics occurred in Scotland, New Zealand, and Poland.
Blackcurrants were once popular in the United States as well, but became less common in the 20th century after currant farming was banned in the early 1900s, when blackcurrants, as a vector of white pine blister rust, were considered a threat to the U.S. logging industry. The federal ban on growing currants was shifted to the jurisdictions of individual states in 1966, and was lifted in New York State in 2003 through the efforts of horticulturist Greg Quinn. As a result, currant growing is making a comeback in New York, Vermont, Connecticut, and Oregon. However, several statewide bans still exist as of August 2021. Since the American federal ban curtailed currant production nationally for nearly a century, the fruit remains largely unknown in the United States and has yet to regain its previous popularity to levels enjoyed in Europe or New Zealand. Owing to its unique flavour and richness in polyphenols, dietary fibre and essential nutrients, awareness and popularity of blackcurrant is once again growing, with a number of consumer products entering the U.S. market.


The fruit of blackcurrants when eaten raw has a strong, tart flavour. It can be made into jams and jellies which set readily because of the fruit's high content of pectin and acid. For culinary use, the fruit is usually cooked with sugar to produce a purée, which can then be passed through muslin to separate the juice. The purée can be used to make blackcurrant preserves and be included in cheesecakes, yogurt, ice cream, desserts, sorbets, and many other sweet dishes. The exceptionally strong flavour can be moderated by combining it with other fruits, such as raspberries and strawberries in summer pudding, or apples in crumbles and pies. The juice can be used in syrups and cordials. Blackcurrants are a common ingredient of rødgrød, a popular kissel-like dessert in North German and Danish cuisines.
Blackcurrants are also used in savoury cooking. Their astringency creates added flavour in sauces, meats and other dishes. Blackcurrants are included in some unusual combinations of foods. They can be added to tomato and mint to make a salad. Blackcurrants may accompany roast beef, grilled lamb, duck,  seafood and shellfish. Canvasback duck with  blackcurrants was a delicacy in nineteenth century New York. They can provide a dipping sauce at barbecues. They can be blended with mayonnaise, and used to invigorate bananas and other tropical fruits. Blackcurrants can be combined with dark chocolate or added to mincemeat in traditional mince pies at Christmas.
Japan imports US$3.6 million of New Zealand blackcurrants for uses as dietary supplements, snacks, functional food products and as quick-frozen (IQF) produce for culinary production as jams, jellies or preserves.


The juice forms the basis for various cordials, juice drinks, and smoothies. In Britain, 95% of the blackcurrants grown are used to manufacture Ribena (a brand of fruit juice whose name is derived from Ribes nigrum) and similar fruit syrups and juices. Macerated blackcurrants are also the primary ingredient in the apéritif, crème de cassis, which in turn is added to white wine to produce a Kir or to champagne to make a Kir Royal.
In the United Kingdom, a blackcurrant cordial may be mixed with beer or alcoholic cider to make drinks including "cider and black", "lager and black", or "snakebite and black".
In Russia, blackcurrant leaves may be used for flavoring tea or preserves, such as salted cucumbers, and berries for home winemaking. Sweetened vodka may also be infused with blackcurrant leaves making a deep greenish-yellow beverage with a tart flavor and astringent taste. The berries may be infused in a similar manner.
Blackcurrant seed oil is an ingredient in cosmetics preparations, often in combination with vitamin E. The leaves can be extracted to yield a yellow dye, and the fruit is a source for a blue or violet dye resulting from its rich content of anthocyanins.


Raw blackcurrants are 82% water, 15% carbohydrates, 1% protein and 0.4% fat (table). Per 100 g serving providing 63 kilocalories, the raw fruit has high vitamin C content (218% of the Daily Value, DV) and moderate levels of iron and manganese (12% DV each). Other nutrients are present in negligible amounts (less than 10% DV, table).


Polyphenol phytochemicals present in the fruit, seeds and leaves, are being investigated for their potential biological activities. Major anthocyanins in blackcurrant pomace – delphinidin-3-O-glucoside, delphinidin-3-O-rutinoside, cyanidin-3-O-glucoside, and cyanidin-3-O-rutinoside, which are retained in the juice concentrate – are among other polyphenols.
Blackcurrant seed oil is rich in vitamin E and unsaturated fatty acids, including alpha-linolenic acid and gamma-linolenic acid.


The redcurrant or red currant (Ribes rubrum) is a member of the genus Ribes in the gooseberry family. It is native to western Europe. The species is widely cultivated and has escaped into the wild in many regions.
Ribes rubrum is a deciduous shrub normally growing to 1–1.5 metres (3–5 ft) tall, occasionally 2 m (7 ft), with five-lobed leaves arranged spirally on the stems. The flowers are inconspicuous yellow-green, in pendulous 4–8 cm (1+1⁄2–3+1⁄4 in) racemes, maturing into bright red translucent edible berries about 8–12 mm (3⁄8–1⁄2 in) diameter, with 3–10 berries on each raceme. An established bush can produce 3–4 kg (6 lb 10 oz – 8 lb 13 oz) of berries from mid to late summer.


There are several other similar species native in Europe, Asia and North America, also with edible fruit. These include Ribes spicatum (northern Europe and northern Asia), Ribes alpinum (northern Europe), R. schlechtendalii (northeast Europe), R. multiflorum (southeast Europe), R. petraeum (southwest Europe) and R. triste (North America; Newfoundland to Alaska and southward in mountains).
While Ribes rubrum is native to Europe, large berried cultivars of the redcurrant were first produced in Belgium and northern France in the 17th century. In modern times, numerous cultivars have been selected; some of these have escaped gardens and can be found in the wild across Europe and extending into Asia.
The white currant is also a cultivar of Ribes rubrum. Although it is a sweeter and albino variant of the redcurrant, not a separate botanical species, it is sometimes marketed with names such as Ribes sativum or Ribes silvestre, or sold as a different fruit.
Currant bushes prefer partial to full sunlight and can grow in most types of soil. They are relatively low-maintenance plants and can also be used as ornamentation.