Three varieties were recognized by Carl Taylor et al. in 1976 in their treatment of the species: A. platyneuron var. platyneuron, the typical variety, A. platyneuron var. incisum, with more deeply cut pinnae, and A. platyneuron var. bacculum-rubrum, larger and more fertile than the others with toothed pinnae. However, they note that both these varieties intergrade, and Flora of North America does not recognize any infraspecific taxa.  In addition to these varieties, three forms were recognized by Taylor et al. A. platyneuron f. proliferum, discussed below, is not recognized by later treatments. A. platyneuron f. hortonae is only known from sporadic, sterile specimens, with pinnae imbricate and deeply cut and lobed. In A. platyneuron f. furcatum, the rachis is multiply branched near the tip, but the form appears otherwise normal.
Asplenium ebeneum var. bacculum-rubrum was first described in 1871 by Americus Featherman. His epithet refers to Baton Rouge, Louisiana, where he found it growing at the edges of cultivated fields and canebrakes. He described it as standing from 1 to 2 feet (0.3 to 0.6 m) high, with twenty to thirty "elongated" sori on each pinna. A large variety of Asplenium platyneuron found throughout the southeastern United States, with distinct rather than confluent sori, was described by M. L. Fernald in 1935 as Asplenium platyneuron var. euroaustrinum, who was then unaware of Featherman's publication. He subsequently deemed the two to be identical, and transferred Featherman's variety to A. platyneuron, as A. platyneuron var. bacculum-rubrum, in 1936. According to Taylor et al., this variety may be recognized by a longest pinna length greater than 3.5 centimeters (1.4 in) and the almost universal presence of sori on erect fronds. They described it as bearing fertile fronds up to 70 centimeters (28 in), with as many as seventy pinnae, and a coarse appearance with roughly toothed leaf edges intergrading with A. platyneuron var. incisum. Herb Wagner and David M. Johnson, who collected similar material in Cass County, Michigan (well to the northwest of the supposed range of the variety) did not consider morphological variation in var. bacculum-rubrum to be distinct from typical material except for its size, and recommended it be given taxonomic status no higher than that of a form, if recognized at all.
Asplenium ebeneum var. incisum was collected by Elliot C. Howe in Poestenkill, New York and described in 1869 by Charles H. Peck. Although described as having pinnae largely "incised-pinnatifid", most of the pinnae in the type material are doubly serrate (toothed) or serrate-incised. In 1873, Elihu S. Miller collected fronds from Wading River, New York which were wider than usual and sharply serrate. This he named Asplenium ebeneum var. serratum, at the suggestion of Asa Gray. Although Miller's type material has not been located, specimens determined as var. serratum by Gray were found by Taylor et al. to be indistinguishable from var. incisum. However, both epithets continued to be recognized by authors for some time. Britton, Sterns and Poggenburg transferred var. serratum as A. platyneuron var. serratum in 1888; Willard Clute lowered its rank to become A. ebeneum f. serratum in 1901, and the combination at this rank was transferred to A. platyneuron by Ralph Hoffmann in 1922. Benjamin Lincoln Robinson transferred var. incisum to A. platyneuron in 1908, and Farwell recognized var. serratum when he segregated Chamaefilix from Asplenium in 1931. Edgar T. Wherry, in 1940, synonymized not only var. serratum with var. incisum, but included var. bacculum-rubrum and var. euroaustrinum under that epithet. He also created the epithet var. typicum for the normal form of ebony spleenwort. Taylor et al., reviewing these treatments, distinguished var. incisum as having doubly serrate pinnae cut less than 80% of the way to the costa, with normal fertility (unlike the sterile A. platyneuron f. hortonae). As these plants occur throughout the range of the species intermixed with typical specimens and intergrading with them morphologically, Wagner and Johnson did not think them worth of taxonomic recognition.
Another taxon characterized by deeply incised margins was described in 1901 by George E. Davenport as Asplenium ebeneum var. hortonae. These specimens were found in 1900 growing on limestone in Brattleboro, Vermont by Frances B. Horton, for whom Davenport named the variety. In this variety, all the pinnae (including the more reduced basal pinnae) are obliquely toothed or cut very nearly into separate, toothed pinnules. The upright fronds are sterile. Willard Clute treated it as a form, A. ebeneum f. hortonae, in 1906. B. L. Robinson, in 1908, declared A. ebeneum var. hortonae a synonym of A. platyneuron var. incisum. Clute transferred the epithet at the varietal level to form A. platyneuron var. hortonae in 1909, but he also equated this with var. incisum. Lyman B. Smith continued to recognize it in Massachusetts, treating it as the form A. platyneuron f. hortonae in 1928. In 1937, Arthur Leeds explicitly distinguished it at varietal level, noting that a photograph of the type of A. ebeneum var. incisum did not closely correspond to A. ebeneum var. hortonae, having merely toothed rather than deeply cut and overlapping pinnae. Edgar Wherry also explicitly distinguished A. platyneuron var. hortonae from A. platyneuron var. incisum, erroneously duplicating Clute's 1909 combination. Material collected from St. Mary's County, Maryland was described by James E. Benedict, Jr. in 1947 as A. platyneuron f. dissectum, noting that while similar to f. hortonae, some of the pinnae in his material were completely cut into pinnules, which were themselves deeply lobed. Taylor et al. noted that much of Benedict's material, however, resembled typical f. hortonae, although approaching var. bacculum-rubrum in size. They equated f. dissectum with f. hortonae, and noted that specimens of the latter could approach var. incisum and var. bacculum-rubrum. While Wagner and Johnson declined to distinguish most infraspecific taxa within A. platyneuron, they did recognize f. hortonae as a "rare sterile form".
A form with forked fronds was known around the end of the nineteenth century, and was formally described in 1909 by Willard Clute as A. platyneuron f. furcatum. The form differs from normal A. platyneuron only in forking near the apex of the blade. Robert M. Tetrick II discovered similar plants in West Virginia, which he described as having "fronds much branched, the ultimate divisions crested" and named A. platyneuron f. multifidum. Taylor et al. compared the type of this form with Clute's illustration of f. furcatum and considered them to be the same. Wagner & Johnson noted that such forms were a frequent developmental error in many species of North American fern.
The formation of proliferating buds in ebony spleenwort has also given rise to a taxonomic distinction. Bud formation was first observed by the nurseryman Conrad Loddiges in 1817, in specimens in cultivation in Great Britain. However, the phenomenon was overlooked until 1879, when D. C. Eaton observed it in specimens from Florida. He took this for an aberrant variety, which he named A. ebeneum var. proliferum. Willard Clute reduced its status from a variety to a form, A. ebeneum f. proliferum, in 1906. Similar specimens were subsequently reported from Maryland, Pennsylvania, and Connecticut; the buds appeared on the rachis of sterile fronds, and were often only detected when mounting the specimen. In 1924, Frederick G. Floyd argued that the formation of these proliferations was a normal characteristic of the species, which appeared regularly, if not universally, and did not warrant a varietal designation. He also observed the formation of proliferating buds on a fertile rachis of A. ebeneum var. serratum. Floyd's position was not universally accepted: Louise Tanger made a new combination for the form, A. platyneuron f. proliferum in 1933, and Taylor et al. recognized it in a discussion of infraspecific taxa in the species in 1976. However, these authors noted that specimens of A. platyneuron f. proliferum would be assigned to various other varieties if they were not proliferous. Wagner & Johnson, in 1981, declined to recognize the taxon on grounds similar to Floyd's, and Wagner's treatment in Flora of North America does not mention the form.


As part of the "Appalachian Asplenium complex", ebony spleenwort has been found to form hybrids with a number of other spleenworts. The hybrid with mountain spleenwort (A. montanum) has been collected only rarely, but on multiple occasions, this hybrid has undergone chromosome doubling to give rise to the fertile species known as Bradley's spleenwort (A. bradleyi). A backcross between A. bradleyi and A. platyneuron is believed to have been collected twice, from a now-destroyed site in Pennsylvania, and in a preliminary report from Sequatchie County, Tennessee. The hybrid with walking fern (A. rhizophyllum), known as Scott's spleenwort (A. × ebenoides), regularly appears where the two parent species grow together. At one locality, in Havana Glen, Alabama, A. × ebenoides has undergone chromosome doubling to produce a fertile species, Tutwiler's spleenwort (A. tutwilerae). The backcross between A. platyneuron and A. tutwilerae is known as Boydston's spleenwort (A. × boydstoniae), occurring in nature only with A. tutwilerae at Havana Glen. A. platyneuron is also known to hybridize with lobed spleenwort (A. pinnatifidum), a descendant of mountain spleenwort and walking fern, to produce the rare Kentucky spleenwort (A. × kentuckiense). Evidence for these hybridizations was obtained through cytological studies, chromatography, and allozyme electrophoresis.
Outside of the "Appalachian Asplenium complex", A. platyneuron can also hybridize with wall-rue (A. ruta-muraria), forming Morgan's spleenwort (A. × morganii), and with maidenhair spleenwort (A. trichomanes) to form Virginia spleenwort (A. × virginicum). A. × morganii is known from one specimen, collected from a limestone cliff overlooking the Potomac River in Maryland, while A. × virginicum has been collected three times, from Pennsylvania, Virginia, and North Carolina. A hybrid with Asian walking fern, A. ruprechtii, has been produced in cultivation and is informally known as A. × crucibuli in horticulture. It is similar to A. × ebenoides, but the frond is linear in shape, rather than being wider at the base.


In North America, A. platyneuron is native throughout the eastern United States from southern Maine to the southeastern corner of Wisconsin, south to Florida and west to eastern Nebraska, Kansas, Oklahoma, and Texas, and in the far southeast of Canada. It is also found around the meeting point of Colorado, New Mexico, and Oklahoma, and in isolated small populations in New Mexico, Arizona and the West Indies. Outside of North America, A. platyneuron is found in tropical and subtropical southern Africa, a distribution not known for any other North American fern. It ranges from the Western Cape province of South Africa northwards along the eastern seaboard to Gauteng and Mpumalanga provinces, its distribution including Lesotho. An isolated population was found on serpentine soil in an oak woodland in Slovakia in 2009. Since the 1960s, A. platyneuron has spread rapidly and aggressively in the Great Lakes region, where it was formerly uncommon. Though widespread in southern Africa, it is not particularly abundant, and in that part of its range is most commonly found in Lesotho.
Asplenium platyneuron can be found in a wide variety of habitats, at altitudes from 0 to 1,300 meters (0 to 4,300 ft). It will tolerate soils ranging from mediacid (pH 3.5–4.0) to subalkaline (pH 8.0–8.5), although it prefers subacid soils (pH 4.5–5.0) over mediacid. Unlike many other North American spleenworts, it can grow on soil as well as rock. When growing in soil, it can be found in forests and woodlands, including sandy pinelands, as well as old fields and other disturbed sites. It can colonize a variety of rocks, particularly (but not limited to) calcareous ones, and will also grow on mortared walls. In South Africa, it is generally found at altitudes over 600 meters (2,000 ft), in habitats similar to those it prefers in North America (under small bushes and on rocky banks). It typically occurs neither in full shade nor in full sun, but at the base of rocks in grasslands and at forest edges and in Leucosidea scrub.


Protein extracts from A. platyneuron have been shown to deter insect predation on soybeans to a significant extent, and the Missouri Botanical Garden describes it as lacking "serious insect or disease problems". However, a population of several hundred individuals in Florida was reported to have been almost wiped out by insect activity. It is susceptible to slugs. The black fern aphid (Idiopterus nephrelepidis) has been reported to feed on it.
Sporophytes are fairly tolerant of drought, but require well-drained soils. The prothallia (gametophytes) of A. platyneuron can survive periods of drought for up to a month. There is some evidence to show that the prothallia may undergo clonal reproduction and fission, which has been induced in the laboratory through variations in light intensity.
A variety of adaptations make A. platyneuron an aggressive colonizer, even weedy, when compared with other spleenworts, although a warming climate and an increase in second growth habitats may also have played a role in its expansion in the Great Lakes region. It tolerates broad variation in soil conditions, including pH, and will grow in both sun and shade. The starchy stipe bases provide energy for rapid growth in the spring, allowing the fronds to keep ahead of competing vegetation. The erect fertile fronds, unusual for Asplenium, help release spores into the wind for long-distance dispersal, while the proliferative buds allow clonal propagation in moist, fertile habitats. The species also carries a very low genetic load, so that viable sporophytes can develop from intragametophytic self-fertilization with 83–89% success. This means that new sporophytes can usually grow from the gametophyte formed from a single spore. This has allowed ebony spleenwort to be an early colonizer, from distant locations, of recently disturbed habitats, such as coal spoils in southern Iowa. The appearance of A. platyneuron in a disturbed habitat in Slovakia, 6,500 kilometers (4,000 mi) from the nearest known sites in eastern North America, is probably the result of long-distance dispersal, which may also have allowed it to colonize and naturalize in South Africa.
While globally secure, ebony spleenwort is considered an endangered species in some of the states and provinces at the northern and western edges of its North American range. NatureServe considers it to be critically imperiled in Arizona and Colorado, imperiled in Nebraska, Maine, Rhode Island, and Quebec, and vulnerable in Minnesota.


The ebony spleenwort is sometimes grown as a terrarium or garden plant. It can be cultivated in sandy peat, subacid garden soil, other gravelly, sandy or gritty soils, or potting mix under moist to dry conditions. Both acid and alkaline soils are acceptable. Good drainage is essential, and the species will grow even in dry soil. Partial sun or low to high light is recommended, although full shade is tolerated. Plants are said to be easy to maintain once they have become established, but it has been described as "rather difficult" to grow in Germany. Conrad Loddiges found it necessary to use artificial heat to cultivate ebony spleenwort in Great Britain.


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Asplenium scolopendrium, commonly known as the hart's-tongue fern, is an evergreen fern in the genus Asplenium native to the Northern Hemisphere.


The most striking and unusual feature of the fern is its simple, undivided fronds. The leaves' supposed resemblance to the tongue of a hart (an archaic term for a male red deer) gave rise to the common name "hart's-tongue fern".


The Latin specific epithet scolopendrium is derived from the Greek skolopendra, meaning a centipede or millipede; this is due to the sori pattern being reminiscent of a myriapod's legs. The leaves are 10–60 cm long and 3–6 cm broad, with sori arranged in rows perpendicular to the rachis.


A global phylogeny of Asplenium published in 2020 divided the genus into eleven clades, which were given informal names pending further taxonomic study. A. scolopendrium belongs to the "Phyllitis subclade of the "Phyllitis clade. Members of the Phyllitis clade have undivided or pinnatifid leaf blades with a thick, leathery texture, persistent scales on their stalk, and often possess anastomosing veins. Members of the Phyllitis subclade have undivided leaves with freely branching veins and single or paired sori. They are widely distributed through the Northern Hemisphere. Its closest relative within the subclade is A. komarovii, with which it forms a clade (the former segregate genus Phyllitis), sister to A. sagittatum.
Three variations or subspecies are currently known:
A. scolopendrium var. scolopendrium, the most common variation, is native to Eurasia and North Africa;
A. scolopendrium var. americanum, a threatened variation, is native to the United States and Canada;
A. scolopendrium var. lindenii, the least-studied variation, is native to Mexico and Hispaniola.
Morphological differences between the variations are minor, but the North American variations (i.e. americanum and lindenii) are tetraploid, while the Old World variation (i.e. scolopendrium) is diploid. Some taxonomists group lindenii with americanum, leaving just two variations.


Asplenium scolopendrium is a common species in the Old World:
The variation scolopendrium has been found throughout Europe (including the Caucasus and the British Isles), the Middle East, and North Africa (in Morocco, Algeria, Tunisia and Libya, as well as the Canary Islands); it has also been introduced to the Falkland Islands of South America. Specimens of this variation found in North America (such as in New Brunswick and Ontario in Canada, and Maryland in the United States) are considered naturalized descendants of cultivated plants.
In North America, it occurs in rare, widely scattered populations located in different locales:
The variation lindenii grows in the Mexican states of Chiapas, Coahuila, Nuevo León, and Oaxaca, as well as the Caribbean island of Hispaniola.
The variation americanum mostly grows along the Onondaga Limestone and Niagara Escarpment geological formations in Central New York (present in 2 counties), southern Ontario (present in 7 counties), and the eastern Upper Peninsula in Michigan (present in 2 counties). Exceptions are disjunct populations that exist in Alabama (in Fern Cave National Wildlife Refuge, a wildlife refuge centered around an off-limits cave in Jackson County, Alabama, where it has declined heavily due to illegal plant collecting, and an undisclosed pit in Morgan County that is also off-limits and protected), and Tennessee (in just a single county); these southern populations are at dire risk of extirpation. An introduced population descended from New York plants is found in New Jersey; it is a remnant of a 1936 effort to practice ex-situ conservation of populations in New York.
In 2020, a new population of hart's-tongue ferns was discovered inside of a cave with basaltic lava flows in El Malpais National Monument, Cibola County, New Mexico; this represents the first confirmed population of the species in North America west of the Mississippi. Genetic analyses and surveys are currently being performed to determine the population's variation and overall health.


The plants grow on neutral, calcium-rich, and/or lime-rich substrates under deciduous hardwood canopies (usually sugar maples in eastern North America), including moist soil and damp crevices in old walls; they are found most commonly in shaded areas. Plants in full sun are usually stunted and yellowish in colour, while those in full shade are dark green and healthy. The disjunct populations of the North American variation in the southeastern US are found exclusively in sinkhole pits or limestone caves. These populations may be relics of cooler Pleistocene climates.


In the United States, A. scolopendrium var. americanum was declared endangered by the U.S. Fish and Wildlife Service in 1989. The reasons for its rarity are currently being researched, with reintroduction programs in New York and elsewhere also in development.


Ontario, Canada has the highest population numbers of A. scolopendrium var. americanum of any region in the variation's distribution, with around 80% of all subpopulations and around 94% of all individuals. The fern was reported at more than 100 sites across the province, with around 75 still believed to be existing. Despite this, A. scolopendrium var. americanum was listed as  a species of Special Concern under the Committee on the Status of Species at Risk in Ontario in May 2017, due to its extremely specific habitat requirements, relatively small distribution, and some subpopulations consisting of too little individuals.


In spite of being much more common in Europe than in North America (and therefore present in more protected areas), A. scolopendrium is still declining in certain areas of the continent. The fern was listed as "Vulnerable" in the National Red Lists for Albania in 2014 and Norway in 2010 (under Criterion D1); considered "critically threatened and rare" in the Czech Republic's 2012 plant Red List; and "Endangered" in Sweden's 2010 Red List. However, it was not considered threatened in Germany's 1996 Red List of Threatened Plants. A. scolopendrium is protected by law in the Netherlands since 1998.


Asplenium scolopendrium is often grown as an ornamental plant, with several cultivars selected with varying frond form, including with frilled frond margins, forked fronds and cristate forms. The species has gained the Royal Horticultural Society's Award of Garden Merit, as has the cultivar
'Angustatum'.
The American variation is reputed to be difficult to cultivate (making conservation efforts for it even more troublesome); due to this, most, if not all, cultivated individuals are derived from the Old World variation.


This fern was used in the 1800s as a medicinal plant in folk medicine as a spleen tonic (hence an archaic name for the genus, "spleenworts") and for other uses.


Asplenium trichomanes, the maidenhair spleenwort, is a small fern in the spleenwort genus Asplenium. It is a widespread and common species, occurring almost worldwide in a variety of rocky habitats. It is a variable fern with several subspecies.
The specific epithet trichomanes refers to a Greek word for fern.


Asplenium trichomanes grows  10 to 30 cm tall forming tufts arising from a short, scaly rhizome. The scales are dark.  The evergreen fronds are long and narrow, gradually tapering towards the tip. They are simply divided into small, yellow-green to dark-green, roundish pinnae. The stipe and rachis of the frond are dark all along their length. The fronds can reach 40 cm in length but are more commonly 8–20 cm. The indusia are linear to oval, straight, and attached to the upper-side of the fertile vein. There are (2) 4 to 8 sori per pinna and each are 1 to 3.5 mm long. Diploid (2n) chromosome count is 72.


It is widespread in temperate and subarctic areas and also occurs in mountainous regions in the tropics. Its range includes most of Europe and much of Asia south to Turkey, Iran and the Himalayas with a population in Yemen. It occurs in northern, southern and parts of eastern Africa and also in eastern Indonesia, south-east Australia, Tasmania, New Zealand and Hawaii. It is found in North America and Central America and Cuba, and the northern and western regions of South America such as Chile. Even though its range is wide spread, it is often rare, and populations are widely spread out from each other based on the available of suitable habitat.
It grows in rocky habitats such as cliffs, scree slopes, walls and mine waste, the type of rock used as a substrate depending on the subspecies. It grows from sea-level up to 3000 metres in North America while in the British Isles it reaches 870 metres.
In the US state of Minnesota A. trichomanes is listed as a threatened species. It occurs on ledges and in crevices on moist, east-facing cliffs and occasionally on talus with similar conditions. The Minnesota populations are Asplenium trichomanes subsp. trichomanes.


Asplenium trichomanes is valued in cultivation for its hardiness (down to −20 °C (−4 °F)), its evergreen foliage and its ability to colonise crevices in stone walls. It prefers a fully or partially shaded aspect. It has gained the Royal Horticultural Society’s Award of Garden Merit.


Asplenium trichomanes has diploid, tetraploid and hexaploid cytotypes, which it has been argued should be recognised as distinct species. A triploid cytotype (a sterile hybrid between the diploid and tetraploid cytotype) is also known. Within these cytotypes several subspecies are recognised, including
Asplenium trichomanes subsp. trichomanes prefers acidic rocks such as sandstone, basalt and granite. In Europe and North America it is most often found in mountainous areas and is commonest in the north. It is a delicate plant with a slender stipe and rachis and relatively few pinnae. Diploid.
Asplenium trichomanes subsp. quadrivalens prefers calcareous rocks such as limestone and dolomite and often grows on the mortar in walls. It is commoner than A. t. subsp. trichomanes in much of Europe but is less widespread in North America, although it is present in southern North America where ssp. trichomanes is absent. Compared to the nominate subspecies it is stouter and has more pinnae which are more square in shape and have less of a stalk. The fronds tend to grow close to the rock while those of A. t. subsp. trichomanes tend to arch away. Tetraploid.
Asplenium trichomanes subsp. pachyrachis (syn. Asplenium csikii) is mainly found on limestone rocks and walls. It is small and delicate, grows close to the rock and has a rigid, fragile stipe and rachis. Tetraploid.
Asplenium trichomanes subsp. coriaceifolium (syn. Asplenium azomanes): Majorca, Spain, Morocco. Tetraploid.
Asplenium trichomanes subsp. hastatum. Tetraploid.
Asplenium trichomanes subsp. inexpectans. Diploid.
Asplenium trichomanes subsp. maderense. Madeira, Azores. Hexaploid. Hexaploids also occur in Australia and New Zealand.
Asplenium trichomanes nothosubsp. staufferi. Tetraploid (pachyrachis × quadrivalens).
Asplenium trichomanes nothosubsp. barraraense. Tetraploid (coraceifolium × quadrivalens).
Asplenium trichomanes nothosubsp. lovisianum. Tetraploid (hastatum × quadrivalens).
Asplenium trichomanes nothosubsp. moravicum. Tetraploid (hastatum × pachyrachis).
Asplenium trichomanes nothosubsp. melzeranum. Triploid (hastatum × inexpectans).
Asplenium trichomanes nothosubsp. melzeri. Triploid (quadrivalens × inexpectans).
Asplenium trichomanes nothosubsp. tadei-reichsteinii. Triploid (pachyrachis × inexpectans).
Asplenium trichomanes nothosubsp. lusaticum. Triploid (trichomanes × quadrivalens).
Asplenium trichomanes nothosubsp. malacitense. Triploid (coraceifolium × inexpectans).


Asplenium viride is a species of fern known as the green spleenwort because of its green stipes and rachides. This feature easily distinguishes it from the very similar-looking maidenhair spleenwort, Asplenium trichomanes.


Green spleenwort was described by Carl Linnaeus in his 1753 Species Plantarum, under the name "Asplenium Trich. ramosum", with a type locality of "in Arvorniæ rupibus" (rocks in Caernarfonshire). Under the rules of the International Code of Botanical Nomenclature, phrase names such as "Asplenium Trichomanes ramosum" are to be treated as orthographic errors – in this case, for "Asplenium ramosum". That name was later rejected in favour of William Hudson's later name Asplenium viride, which had a type locality of "in rupibus humidis in montibus Walliæ et in comitatibus Eboracensi et Westmorlandico" (damp rocks in the mountains of Wales, Yorkshire and Westmorland).
A global phylogeny of Asplenium published in 2020 divided the genus into eleven clades, which were given informal names pending further taxonomic study. A. viride belongs to the "A. viride subclade" of the "A. trichomanes clade". The A. trichomanes clade has a worldwide distribution. Members of the clade grow on rocks and usually have once-pinnate leaf blades with slender, chestnut- to dark-brown stalks. The A. viride subclade, which contains only A. viride and its allopolyploid descendant A. adulterinum, is exceptional in having green stalks.


A. viride is a native species of northern and western North America and northern Europe and Asia. It is a small rock fern, growing on calcareous rock. It is a diploid species, with n = 36, and hybridizes with Asplenium trichomanes to produce Asplenium × adulterinum, found on Vancouver Island, British Columbia.


Astelia nervosa, also known as mountain astelia or, along with a number of other species, as bush flax, is a herbaceous plant native to New Zealand. A. nervosa has long, flexible, leathery leaves that are light green and grey in colour. The flowers are light brown to red in colour. The mature fruits are generally orange.
It is found in lowland to low alpine areas from the southern North Island south to Stewart Island.


Asterella californica is a complex thallic liverwort in the phylum Marchantiophyta. A. californica often grows as colonies of flat rosettes of light green, rigid thalli, with undersides dark wine-red to nearly black. The receptacles are rounded, with four lobes each bearing a single sporangium sheathed by a white tattered skirt. A. californica is dioecious with separate male plants often intermingled with female plants. This species is found throughout California from San Francisco southward to San Diego and Guadalupe Island. Asterella californica is the commonest species of the three species of Asterella occurring in California; the other two species are A. bolanderi and A. palmeri.


Plants are pale green dorsally with purple ascending margins and dark purple undersides, thallus edges tending to curl upward exposing the dark underside when dry. Thalli are simple or somewhat sparingly dichotomous, 8–25 mm long, usually 1-3 times dichotomous, the ultimate segments emarginated, obovate, obcordate, or broadly oblong, indistinctly areolate, 4–12 mm in maximum width. The plants dry up during the long rainless summers, but the ends of the branches remain alive, so that each growing tip becomes the beginnings of a new plant. It was found that a surprisingly large amount of the thallus remains alive, and within a few hours after the dried plants are supplied with water, the forward part of the thallus has assumed its active condition and begins to grow. In Asterella the first antheridia were mature in about two weeks. This early development of the reproductive organs raised the question whether they might not begin their development before the close of the growing period in the spring.


Antheridia are clearly circumscribed, slightly elevated, strongly papillate, oval to linear-oblong, sometimes forked discs, situated in the median line of the thallus at some distance back from the apex. While working on male individuals in his laboratory George Pierce observed, then measured, antherozoids–packets of ciliated sperm cells and encasing slime–being "forceably ejected" from the thallus. One may say, then, that Asterella can throw its antherozoids, under favorable conditions, to a vertical height of 14–20 cm.


Each "umbrella", or archegoniophore, is clearly visible raised above the thallus of mature female plants is not itself a sporophyte but is in fact gametophyte tissue. The part of the "umbrella" at the top of the stem is called the female receptacle or carpocephalum. The receptacle is initially on the thallus surface and the stalk grows to raise it. The archegonia are found on the female receptacle and initially they are in the upper surface and face upward. They are fertilized when the stem is still fairly short. The stem continues to grow and the receptacle continues to grow by centrally added tissue. This moves the fertilized archegonia outward and the receptacle eventually folds over to orient the developing sporophytes so that they face down.
Peduncle straw-colored sometimes with a brown or purplish pigmentation, 1–3 cm high. Disk of receptacle green, about 5 mm across, low-hemispherical, deeply lobed, almost smooth, the lobes mostly 4 (sometimes 5).


Capsule circumscissile at the middle or above by an irregular line, the operculum breaking up into fragments. Spores yellow, mostly 100 to 120 µm in diameter, with wavy wings 12-20 µm wide along the edges, the surface covered over more or less completely with a fine and often irregular reticulum with meshes 3-4 µm across. Elaters yellow variously curved, mostly 240-450 µm long and 12-16 µm wide. The yellow spores with their distinct marginal wings, fine surface reticulation, and sparesly developed ridges on the faces are also very distinctive of the species.


Asterella californica is widespread and common on lightly shaded slopes and banks and around rock outcrops, mostly in oak forest, chaparral on desert scrub, mostly below 3000 feet (but to 7000 feet in San Bernardino County). A. californica occurs throughout the Coast Ranges, western Klamath Ranges, Sacramento Valley, west slope of the Sierra Nevada, coastal Southern California and the Channel Islands, Transverse and Peninsular Ranges, western Colorado Desert; east to Arizona, north to southwestern Oregon, and south to northern Baja California. Growing on mineral soil or among rocks on mineral soil on open or lightly shaded banks.


Astragalus alpinus is a species of flowering plant in the legume family known by the common name alpine milkvetch. It has a circumpolar distribution, occurring throughout the upper latitudes of the Northern Hemisphere.


It is widespread in Eurasia. In North America it occurs from Alaska to Newfoundland and as far south as Nevada and New Mexico.


This plant is variable in appearance. In general, it is a perennial herb growing from a taproot and rhizome network topped with an underground caudex. The roots have nitrogen-fixing nodules. The aboveground stems are up to 30 centimetres (12 in) long and are mostly decumbent, forming a mat. The leaves are up to 15 centimetres (5+5⁄6 in) long and are made up of several pairs of leaflets each up to 2 centimetres (5⁄6 in) long. The inflorescence is a raceme of up to 30 flowers each about 1 centimetre (1⁄3 in) long. The flowers are purple or blue. The fruit is a legume pod up to 1.7 centimetres (2⁄3 in) long which contains seeds.


This plant grows in subalpine and alpine climates, often in moist areas, such as woodlands and meadows around streams and lakes. It also occurs on tundra and other cold, dry, exposed areas. It occurs on gravel bars and scree. It is sometimes a pioneer species, colonizing land in the primary phase of ecological succession, such as roads and bare land turned over during frost heave. It has been observed regrowing early in recently burned areas in Grand Teton National Park. It also grows in vegetated areas. Plants occurring in harsh conditions are smaller than those in more favorable sites.
This plant species provides food for caribou, Arctic hares, greater snow geese, small blue butterflies, and grizzly bears.
This species may be divided into two varieties, var. alpinus occurring in the Arctic and var. brunetianus occurring in northeastern North America at lower latitudes.


Astragalus cicer, the chickpea milkvetch, chick-pea milk-vetch or cicer milkvetch, is a perennial flowering plant native to Eastern Europe, popularized and subsequently transported to areas in Southern Europe, North America, and South America. Cicer milkvetch exhibits legume-like qualities; the plant produces pods which harbor its seeds. Its flowers are usually of pale yellow tint (sometimes white), and as such, attract bumble or European honey bees for pollination. Growth often exceeds 0.6 meters, up to a height of 1 meter in length.


Astragalus cicer is suited best to grow in the Rocky Mountain area in the United States; however, it has been shown that cicer milkvetch also flourishes in coastal areas – and more specifically has been found to perform well in the coasts of Alaska. Because cicer milkvetch displays high tolerance to drought, it has been shown to abide in dry-land locations such as Idaho, Montana, and Wyoming – all of which are areas that often receive less than 14 inches of yearly rain.


Flowers of Astragalus cicer are pale yellow and 15–16 cm in length. Cicer milkvetch employs inflorescence of its flowers, where 15 to 60 flowers grow in a raceme (type of inflorescence, as illustrated in the adjacent image). The flowers of a cicer milkvetch are radial in symmetry and exhibit a 5-lobed "hairy" calyx. They are also asympetalous, in that the petals of the flower are not fused.  Stamens come in sets of 9 to 10. Cicer milkvetch bears fruit in the form of a legume, and is thus dehiscent. Pods also exhibit a pale yellow color, whilst turning black when fully mature.


Astragalus crassicarpus, known as ground plum or buffalo plum, is a perennial species of flowering plant in the legume family, Fabaceae, native to North America. It was described in 1813. The fruit is edible and was used by Native Americans as food and horse medicine.  It is a host of afranius duskywing larvae. It is also known as groundplum milkvetch and pomme de prairie.


The species is 1 to 2 feet tall with pinkish purple flowers and edible fruit pods. The plant grows from thick taproots and several long hairy stems lay on the ground. Its leaves are alternate, between 4–13 cm long, each with 15–27 leaflets that are either elliptic or oblong. The flowers grow in elongated groups among the leaves and the fleshy fruit, measuring 1.5 to 2.5 cm in width, is round. It blooms from May to June.
Astragalus crassicarpus is known as ground plum, though it shares this name with some other species in the genus Astragalus such as Astragalus plattensis. The two species are sometimes confused, though in general, the fruiting pods of A. crassicarpus are glabrous (hairless) while those of A. plattensis are hairy.


Astragalus crassicarpus grows primarily in the Great Plains of Canada and the United States, from British Columbia east to Ontario and south to Texas. It has been recorded as far east as Will County, Illinois, but whether it was originally native to this area or an introduction is unknown.
Ground plums grow in sunny drained soil. They can be found in prairies, pastures, limestone out-croppings and rocky open woods throughout the Mississippi Valley. It is common throughout much of the southern parts of its range.


The name crassicarpus (from both Latin and Greek) means "thick fruited" which refers to the plant's fleshy fruits. The Dakota people gave the plant the name "pte ta wote" (buffalo food), while the Omaha and Ponca people gave the plant two names, "tdika shande" and "wamide wenigthe" (something to go with seed). The Omaha and Ponca used the plant to prepare corn seed for planting. The Dakota ate the fruit right off of the plant and the Pawnee ate them to sate their thirst. The fruit dries out once the seeds ripen, making them become tough and inedible by midsummer. It was used as medicine for horses by the Lakota people.
It is a food source for sheep and cattle. Although the fruit is edible, the rest of the plant is poisonous. The immature fruit can be eaten raw, cooked, or pickled. Its fruit tastes like a sweet pea and they were eaten by the original inhabitants of the prairie, though the raw fruit has been described as "hardly appetizing". The cooked fruits taste like string beans. Similar looking species are completely poisonous. The afranius duskywing butterfly (Erynnis afranius) uses the plant as a host for its larvae.


Astragalus glycyphyllos (liquorice milkvetch, wild liquorice, wild licorice) is a flowering plant in the family Fabaceae, native to Europe. It is a perennial herbaceous plant which is sometimes used for tea.


Astragalus lentiginosus is a species of legume native to western North America where it grows in a range of habitats. Common names include spotted locoweed and freckled milkvetch. There are a great number of wild varieties. The flower and the fruit of an individual plant are generally needed to identify the specific variety.


As a species, Astragalus lentiginosus is distributed throughout the Great Basin of North America, west from the Rocky Mountains to the California Coast Ranges, south to Mexico, and north to British Columbia.  Varieties are largely limited to marginal habitats such as disturbed sites in the arid regions of the continent.  The group also contains a number of edaphic specialists which occur at desert seeps, which frequently exhibit high levels of calcium carbonate.


Astragalus lentiginosus is a perennial or occasionally annual herb with leaves up to 15 centimetres (5.9 inches) long divided into many pairs of small leaflets. The plant is prostrate to erect in form and quite woolly to nearly hairless. The inflorescence holds up to 50 pea-like flowers which may be purplish or whitish or a mix of both. A unifying character among most of the varieties is an inflated, beaked legume pod with a groove along the side. The pod dries to a papery texture and dehisces starting at the beak to release the seeds. The epithet lentiginosus refers to the red mottling commonly found on the pods which resemble freckles.


Many of what we currently know as varieties of Astragalus lentiginosus were originally described as individual species. Botanist Marcus E. Jones was the first to recognize the similarities among these taxa and arranged them as varieties of one species. Per Axel Rydberg employed a very different species concept stating that he did not believe in infrataxa  This resulted in his raising Jones's varieties to species in the genera Cystium and Tium. A notable novelty of Rydberg's treatment is the concept of sections which have been maintained in the keys of subsequent treatments, even if this was not explicitly stated.
Subsequent treatments include Barneby, Isely, and Welsh.  Each of these treatments are slightly different, containing between 36 and 42 taxa.  Recent molecular work seems to suggest a genetic component to the varieties.


Two rare varieties endemic to California are federally listed under the Endangered Species Act; var. coachellae, or Coachella Valley milk vetch, is endangered and var. piscinensis is threatened.


Astragalus lentiginosus is currently not cultivated commercially.  Propagation from seed requires scarification of the seed coat in order for the embryo to absorb water.


The Zuni people  eat the pods of the diphysus variety  fresh, boiled, or salted. They are also dried and stored for winter use.


Astragalus mollissimus (common name - wooly locoweed) is a perennial plant in the legume family (Fabaceae) found in the Colorado Plateau and Canyonlands region of the southwestern United States.


It is hairy a perennial plant growing from 2 to 34 inches (5.1 to 86.4 cm) tall, from a very short stem.


It has hairy stems and leaves. "Mollissumus" means "most soft", referring to the hairy covering of the leaves and stems. Pinnate leaves are from 3⁄4 to 11 inches (1.9 to 27.9 cm) long, with 15–35 elliptical to oval wooly leaflets.


It blooms from March to August. The inflorescence are from 3⁄4 to 10 inches (1.9 to 25.4 cm) stalks with 7–20 flowers per stalk. Each pink to purple or bicolored with white flower has a 1⁄4 to 1⁄2 inch (0.64 to 1.27 cm) hairy calyx with 5 pointed teeth, around a 3⁄4 inch (1.9 cm) corolla with upper petal flares at the end. Seed pods are 1⁄3 to 1 inch (0.85 to 2.54 cm), egg shaped and densely hairy.


It grows from grasslands to Pinyon juniper woodland communities ranging from Wyoming to Arizona.


The plant derives its common name from its wooly stems and leaves, and its effect on the nervous system of livestock which consume it, causing them to "go loco." This is caused by an alkaloid it contains called swainsonine, formerly known as locoine. The plant is toxic both fresh and dried, and in addition to its effects on the nervous system, can also cause congenital defects and liver damage.


Astragalus nuttallianus is a species of milkvetch known by the common names smallflower milkvetch and turkeypeas. It is native to the southwestern and south central United States and northern Mexico, where it can be found in many types of habitat, often in dry areas.
This is an annual herb which is variable in appearance, especially across varieties. It produces slender, hairy stems which reach 4 to 45 centimeters in length. The leaves are up to 6.5 centimeters long and are made up of several oval-shaped pointed or round-tipped leaflets. The inflorescence bears 1 to 4 white to purple or bicolored flowers, each less than a centimeter in length. The fruit is a legume pod 12 to 26 mm long.
There are several varieties of this species:
A. n. var. austrinus - distributed from California to Oklahoma to northwestern Mexico
A. n. var. cedrosensis - native to the Sonoran Desert
A. n. var. imperfectus - native to the southwestern United States
A. n. var. macilentus - native to New Mexico and Texas
A. n. var. micranthiformis - found in the southwestern United States
A. n. var. nuttallianus - known from the central US from Kansas to Louisiana
A. n. var. trichocarpus - native to Texas and Oklahoma
A. n. var. zapatanus - Texas endemic


Astragalus trichopodus is a species of legume known by the common name Santa Barbara milk vetch. It is native to southern California and Baja California, where it grows in several types of open habitat, including in the Transverse Ranges and Mojave Desert.


This is a robust perennial herb producing a branching stem up to about a meter in maximum height. The hairy stem is lined with many leaves each up to 20 cm (7.9 in) long which are made up of several pairs of widely spaced lance-shaped leaflets each up to 2.5 cm (0.98 in) in length. The inflorescence is a raceme of up to 50 flowers which are cream colored and sometimes tinted with light purple. Each flower is 2 to 3 cm (0.79 to 1.18 in) long including its tubular base of sepals.
The fruit is a laterally compressed, slightly inflated legume pod up to 4 to 5 cm (1.6 to 2.0 in) long which dries to a papery texture. The fruits hang in bunches where they develop from the inflorescence. Each pod contains many seeds.


Astrantia major, the great masterwort, is a species of flowering plant in the family Apiaceae, native to central and eastern Europe. Growing to 90 cm (35 in) tall by 45 cm (18 in) broad, it is an herbaceous perennial, much used in gardens.


The Latin specific epithet major, meaning "larger", distinguishes this species from its smaller relative Astrantia minor.


Astrantia major reaches on average 60 centimetres (24 in) of height. The stem is erect and  glabrous, with little branches and few leaves. The basal leaves have a long petiole 10–20 centimetres (3.9–7.9 in), 3 to 7 lobes and toothed segments. Size: 8–15 centimetres (3.1–5.9 in). The cauline leaves are generally two, sessile, amplexicaul and  lanceolate-shaped with a trilobed apex. The inflorescence is umbrella-shaped, with 2–3 centimetres (0.79–1.18 in) of diameter. The floral bracts are numerous (10 - 20), 10–18 millimetres (0.39–0.71 in) long, reddish (sometimes white) with acuminate apex.  The small flowers are greenish-white with reddish shades.  The central ones are hermaphrodite, while the external ones are male. The petals are five, white (or slightly reddened), while the stamens are five and much longer. Size of the flowers: about 1 mm. The flowering period extends from June through September.


The plant also produces an essential oil that can be used in herbal medicines.


Astrantia major is an entomophilous plant, mainly pollinated by beetles, but also by other insects. This perennial plant reproduces itself also by means of buds present at the ground level.


This plant is native to southern Europe (the Pyrenees, Carpathians and Balkans), but also in the Caucasus up to Anatolia. It has been in the British Isles since the 16th century. It has also naturalized in Shropshire near Stokesay Castle, and in Worcestershire.
It is common in mountain meadows and grasslands, in forests and clearings, and close to the streams, usually on calcareous soils, at an elevation of 100–2,300 metres (330–7,550 ft) above sea level.


Astrantia major L. subsp. carinthiaca (Hoppe) Arcang. : Larger umbels  (4–5 cm in diameter) widespread mainly in the eastern Alps.
Astrantia major var. involucrata Koch
Astrantia major L. subsp. elatior (Frivaldsky) Maly: bracts with 5 nerves and with notched apex; teeth of the calyx are very long; widespread in the Apennines.
Astrantia caucasica Auct. Fl.Ital non Sprengel
Astrantia major L. subsp. major
Astrantia major subsp. biebersteinii (Fisch. & C.A.Mey.) I.Grint. (with synonyms of Astrantia biebersteinii Fisch. & C.A.Mey.,Astrantia colchica Albov, Astrantia intermedia Bieb., Astrantia neglecta C.Koch & Bouche, Astrantia orientalis Woronow, Astrantia ossica Woronow and Astrantia trifida Hoffm. )


Many strains of Astrantia  major grow well in the garden, given some shade and moisture. Their flowerheads provide summer colour in shades of red, pink and white.  The following cultivars have gained the Royal Horticultural Society's Award of Garden Merit:-
A. major 'Roma'
'Sunningdale Variegated'
Other cultivars include:-
'Abbey Road'
'Ruby Cloud'
'Rubra'
'Snow Star'
'Lars'
'Moulin Rouge'
'Star of Heaven'
'Rosea'
'Princess Sturdza'
'Venice'
'Magnum Blush'
'Star of Beauty'
'Vanilla Gorilla'
'Roma'
'Hadspen Blood' (a hybrid crossed with Astrantia maxima)
'Shaggy' (previously 'Margey Fish')


Astraptes fulgerator, the two-barred flasher, is a spread-wing skipper butterfly in the genus Astraptes which may constitute a possible cryptic species complex. It ranges all over the Americas, from the southern United States to northern Argentina.


Astraptes fulgerator's adults all look quite alike. They are mid-sized skipper butterflies with the typical wing shape of this group. The upperside is black, with basal to postbasal blue corners which are more extensive on the forewings. There is one discal-tomal and one apical band on the forewing; these are usually off white to light blue but the former may be quite white towards the costal margin. The thorax has bluish hair on the back, the underside is yellow to orange.
The caterpillars and pupae show a wide range of colors and patterns, and the caterpillars also vary in food preference. Last-instar caterpillars are black with a pattern consisting of light to bright yellow dots along the sides, or rings of varying thickness, sometimes interrupted on the back, in a range of colors varying from white to orange red.


This species is highly polyphagous, with most food plants belonging to the Fabaceae (legume family):
Selected primary food plants
Fabaceae
Inga: I. exalata, I. oerstediana, I. punctata, I. sapindoides, I. vera and probably others
Lonchocarpus (see also below)
Senna: candle bush (S. alata), S. cobanensis, S. hayesiana, S. pallida, S. papillosa, S. undulata and probably others
Malvaceae
Hampea appendiculata (but see below)
Sapindaceae
Cupania: C. glabra, C. guatemalensis and probably others
Selected secondary and accidental food plants
Capparaceae
Capparis frondosa
Fabaceae
Canavalia brasiliensis
Cassia: golden shower tree (C. fistula), C. grandis and possibly others
Centrosema (butterfly peas): C. macrocarpum, C. plumieri and possibly others
Desmodium glabrum
Dioclea: D. malacocarpa, D. violacea and possibly others
Mucuna holtonii
Piscidia carthagenensis
Malvaceae
Byttneria catalpaefolia
Rhamnaceae
Karwinskia calderoni
Salicaceae
Casearia sylvestris
Styracaceae
Styrax argenteus


Due to the diversity of caterpillar colors and food plants it was suspected that the butterflies referred to as Astraptes fulgerator might be more than a single species. A controversial 2004 DNA barcoding study of a 648 base pair sequence from the Cytochrome c oxidase (COI) DNA sequence by Paul D. N. Hébert et al. led the authors to claim that at least ten sympatric populations in the Area de Conservación Guanacaste World Heritage Site in northwestern Costa Rica were in various stages of reproductive isolation. However, a later reanalysis of the same DNA sequence data using neighbor joining bootstrap, population aggregation analysis and cladistic haplotype analysis found that: "[a]t least three, but not more than seven mtDNA clades that may correspond to cryptic species are supported by the evidence". Also, where a specific DNA sequence did not correspond to its purported host plant, it was "simply dismissed with an ad hoc hypothesis and manifestly incorrect explanation" by Hébert and his coworkers. The improper use of taxonomic vocabulary was also criticized; Hébert et al. apply the terms "species" and "taxa" as if they were synonymous, but never actually validly described their proposed "species".


The exact number of taxa involved is disputed, most of the "species" detected by the DNA barcoding study seem to be nothing more than morphs or incipient subspecies, coupled with a serious underestimation of variation. Still, two lineages appear to be well distinct and separable at least as subspecies: "CELT" has larvae with bold orange bands in the last instar, which were recorded only on Celtis iguanaea (Ulmaceae); "TRIGO" last-instar larvae have bold yellow bands and were found on the Malpighiales Trigonia (T. arborea, T. laevia and T. rugosa) and, apparently accidentally, on Licania arborea.
Three more lineages are in need of further study. One, "NUMT", was initially dismissed as a numt pseudogene combined with sequencing error but may represent a hitherto unrecognized taxon. Two other lineages, "LOHAM" and "LONCHO", were considered highly distinct in the barcoding study but the reanalysis showed that this might be an error. The latter two are peculiar in some aspects, such as apparently never having bands or orange colors in the last instar stage and showing a preference for Lonchocarpus costaricensis, Lonchocarpus oliganthus, and Hampea appendiculata as larval food but are not monophagous. They appear to be an intermediate stage in lineage sorting and might be considered one or two subspecies if the two most distinct lineages are split off as species.
The other lineages show a marked lack of agreement between morphological, ecological and genetical variation in the reanalysis of the supposed clusters. The entire range of caterpillar colors and patterns is found across one huge ill-structured cluster of genetic diversity. They are polyphagous, feeding preferentially on Inga and Senna as well as a variety of other plants, but apparently not on those preferred by the more distinct lineages except Hampea appendiculata.
The proposed divergence times for the lineages are derived from a standard molecular clock model, which is today known to be incorrect.


Hebert et al. (2004)
Area de Conservación Guanacaste World Heritage Site, NW Costa Rica: Hébert et al. (2004)
Hébert et al. (2004) refer to "Cassia emarginata", which today is either of Chamaecrista pilosa, Rambling Senna (S. bicapsularis) or Senna candolleana. The last does not occur in their study area; given the general importance of Senna species and the lack of records for Chamaecrista species as food plants in the study area, S. bicapsularis seems to be the plant in question.
Brower (2006)


The spotted owlet (Athene brama) is a small owl which breeds in tropical Asia from mainland India to Southeast Asia. A common resident of open habitats including farmland and human habitation, it has adapted to living in cities. They roost in small groups in the hollows of trees or in cavities in rocks or buildings. It nests in a hole in a tree or building, laying 3–5 eggs. The species shows great variation including clinal variation in size and forms a superspecies with the very similar little owl.


The spotted owlet is a small and stocky bird, barely 21 centimetres (8.3 in) in size. The upperparts are grey-brown, heavily spotted with white. The underparts are white, streaked with brown. The facial disc is pale and the iris is yellow. There is a white neckband and supercilium. Sexes are similar. The flight is deeply undulating. The nominate form is darker than the paler forms such as indica of drier regions.


Early workers sometimes treated members of this species group as subspecies of Athene noctua. The two have been separated but they are considered to form a superspecies complex. Several subspecies have been described and about four or five are widely accepted (the race poikila is invalid and refers to Aegolius funereus A. b. fryi of southern India described by Stuart Baker and A. b. mayri described by Deignan from northern Thailand are not usually recognized.). The five widely recognized subspecies are albida Koelz, 1950 of western Asia in Iran and Pakistan; indica (Franklin, 1831) of northern India;  brama (Temminck, 1821) of southern India which is darker than indica; ultra Ripley, 1948 (not always recognized) of northeastern India is said to have the white spots on mantle much and "higher pitched calls"; and pulchra Hume, 1873 of Southeast Asia from Myanmar and Thailand extending into Cambodia and Vietnam. The northern and southern Indian populations intergrade and there is no dividing boundary. The northern indica populations have the upperparts brownish. Size decreases from north to south. The species is not found in Sri Lanka, although birds on the Indian mainland are found even at the tip of Rameshwaram.


This species is nocturnal but is often seen during the day. When disturbed from their daytime site, they bob their head and stare at intruders. Their presence can often be located by the small birds that mob the owlets while they are perching in a tree during daytime. They hunt a variety of insects and small vertebrates. In Pakistan they have been found to take mostly insect prey. In the arid region of Jodhpur, they have been found to take more rodents (especially in the genus Mus and tend to avoid other rodents such as Tatera) prior to the breeding season. Bats, toads, small snakes such as Ramphotyphlops braminus have been noted. They may also take scorpions and molluscs. Nests near human habitations may show higher breeding success due to increased availability of rodents for feeding young.
The call is a harsh and loud churring and chuckling chirurr-chirurr-chirurr ending with a chirwak-chirwak and they call mainly during early dawn or just after sunset.
The breeding season is November to April. Courtship behaviour includes bill grasping, allopreening and ritual feeding. The female may call with the male, bob head and deflect its tail in invitation. The social organization of family groups is not clear and multiple males may copulate with a female and females may attempt pseudocopulation, possibly a kind of displacement behaviour. They nest in cavities often competing with other hole-nesters such as mynas, rollers and parakeets. They may also nest in holes in vertical embankments. The nest may be lined with leaves and feathers or may use the existing lining from a prior occupant. The typical clutch is made up of three or four spherical white eggs (30.9mm long and 26.3 mm wide, 11.6g) and incubation begins with the first laid eggs leading to a wide variation in the size of the chicks. The young are fed initially on insects such as cockroaches and later fed small vertebrate prey such as mice (a toad Bufo stomaticus has been noted in Gujarat). The chicks gain weight during the early stages but lose weight before fledging. Only one or two chicks may fledge and they leave the nest in about a month.
The brain has a pineal gland, formerly thought to be absent in the owls. Birds show variation in the melatonin concentration between day and night. A high melatonin level is associated with sleep and low levels are associated with high alertness and foraging activity. Spotted owlets, however, show only a slightly lower melatonin concentration at night with a slight increase in the early afternoon. Other owls such as the barn owl show little day-night variation. Seasonal changes in glandular activity have been associated with environmental factors such as temperature and humidity.
A coccidian parasites, Eimeria atheni, has been described from this species. An ectoparasitic mite, Neocheletiella athene, has been described from a specimen from the Antwerp zoo. Bird lice of the species Colpocephalum pectinatum are known to be ectoparasites. The Acanthocephalan parasite Apororhynchus chauhani was discovered in the intestine of the spotted owlet.


The burrowing owl (Athene cunicularia), also called the Shoco, is a small, long-legged owl found throughout open landscapes of North and South America. Burrowing owls can be found in grasslands, rangelands, agricultural areas, deserts, or any other open, dry area with low vegetation. They nest and roost in burrows, such as those excavated by prairie dogs (Cynomys spp.). Unlike most owls, burrowing owls are often active during the day, although they tend to avoid the midday heat. Like many other kinds of owls, though, burrowing owls do most of their hunting during dusk and dawn, when they can use their night vision and hearing to their advantage. Living in open grasslands as opposed to forests, the burrowing owl has developed longer legs that enable it to sprint, as well as fly, when hunting.


The burrowing owl was formally described by Spanish naturalist Juan Ignacio Molina in 1782 under the binomial name Strix cunicularia from a specimen collected in Chile. The specific epithet is from the Latin cunicularius meaning "burrower" or "miner". The burrowing owl is now placed in the genus Athene that was introduced by German zoologist Friedrich Boie in 1822.
The burrowing owl is sometimes classified in the monotypic genus Speotyto based on an overall different morphology and karyotype. Osteology and DNA sequence data, though, suggest that the burrowing owl is a terrestrial member of the little owls (Athene), and it is today placed in that genus by most authorities.
A considerable number of subspecies have been described, but they differ little in appearance and the taxonomy of several of them needs to be validated. Most subspecies are found in/near the Andes and in the Antilles. Although distinct from each other, the relationship of the Florida subspecies to (and its distinctness from) the Caribbean birds is not quite clear.
Th 18 recognised subspecies, of which two are now extinct, are:
†A. c. amaura (Lawrence, 1878): Antiguan burrowing owl – formerly Antigua, Saint Kitts, and Nevis Islands, extinct (circa 1905)
A. c. boliviana (L. Kelso, 1939): Bolivian burrowing owl – the Bolivian altiplano
A. c. brachyptera (Richmond, 1896): Margarita Island burrowing owl – Margarita Island, might include A. c.apurensis
A. c. carrikeri (Stone, 1922): east Colombian burrowing owl – eastern Colombia, doubtfully distinct from A. c. tolimae
A. c. cunicularia (Molina, 1782):- southern burrowing owl – lowlands of southern Bolivia and southern Brazil south to Tierra del Fuego, probably
 A. c. floridana (Ridgway, 1874): Florida burrowing owl – Florida and the Bahamas
A. c. grallaria (Temminck, 1822): Brazilian burrowing owl – central and eastern Brazil
†A. c. guadeloupensis (Ridgway, 1874): Guadeloupe burrowing owl – formerly Guadeloupe and Marie-Galante Islands, extinct (circa 1890)
A. c. guantanamensis (Garrido, 2001): Cuban burrowing owl – Cuba and Isla de la Juventud
A. c. hypugaea (Bonaparte, 1825): western burrowing owl – southern Canada through the Great Plains south to Central America
A. c. juninensis (Berlepsch & Stolzmann, 1902): south Andean burrowing owl – Andes from central Peru to northwestern Argentina, might include A. c. punensis.
A. c. minor (Cory, 1918): Guyanese burrowing owl – southern Guyana and Roraima region
A. c. nanodes (Berlepsch & Stolzmann, 1892): southwest Peruvian burrowing owl – southwestern Peru, might include A. c. intermedia
A. c. pichinchae (Boetticher, 1929): west Ecuadorean burrowing owl – western Ecuador
A. c. rostrata (C. H. Townsend, 1890): Revillagigedo burrowing owl – Clarion Island, Revillagigedo Islands
A. c. tolimae (Stone, 1899): west Colombian burrowing owl – western Colombia, might include A. c. carrikeri
A. c. troglodytes (Wetmore & Swales, 1931): Hispaniolan burrowing owl – Hispaniola, Gonâve Island and Beata Island
includes A. c. partridgei (Olrog, 1976): Corrientes burrowing owl – Corrientes Province, Argentina, probably not distinct from A. c. cunicularia
A paleosubspecies, A. c. providentiae, has been described from fossil remains from the Pleistocene of the Bahamas. How these birds relate to the extant A. c. floridana – that is, whether they were among the ancestors of that subspecies, or whether they represented a more distant lineage that completely disappeared later – is unknown.
In addition, prehistoric fossils of similar owls have been recovered from many islands in the Caribbean (Barbuda, the Cayman Islands, Jamaica, Mona Island and Puerto Rico). These birds became extinct towards the end of the Pleistocene, probably because of ecological and sea-level changes at the end of the last ice age rather than human activity. These fossil owls differed in size from present-day burrowing owls and their relationship to the modern taxon has not been resolved.


Burrowing owls have bright eyes; their beaks can be dark yellow or gray depending on the subspecies. They lack ear tufts and have a flattened facial disc. The owls have prominent white eyebrows and a white "chin" patch which they expand and display during certain behaviors, such as a bobbing of the head when agitated.
Adults have brown heads and wings with white spotting. Their chests and abdomens are white with variable brown spotting or barring, also depending on the subspecies. Juvenile owls are similar in appearance, but they lack most of the white spotting above and brown barring below. The juveniles have a buff bar across their upper wings and their breasts may be buff-colored rather than white. Burrowing owls of all ages have grayish legs longer than those of other owls.
Males and females are similar in size and appearance, so display little sexual dimorphism. Females tend to be heavier, but males tend to have longer linear measurements (wing length, tail length, etc.). Adult males appear lighter in color than females because they spend more time outside the burrow during daylight, and their feathers become "sun-bleached". The burrowing owl measures 19–28 cm (7–11 in) long and spans 50.8–61 cm (20–24 in) across the wings, and weighs 140–240 g (5–8 oz). As a size comparison, an average adult is slightly larger than an American robin (Turdus migratorius).


Before European colonization, burrowing owls probably inhabited every suitable area of the New World, but in North America, they have experienced some restrictions in distribution since then. In parts of South America, they are expanding their range with deforestation. The western burrowing owls (A. c. hypugaea) are most common in the Rocky Mountain Arsenal National Wildlife Refuge and in several counties in Colorado and their population is reportedly threatened.
Burrowing owls range from the southern portions of the western Canadian provinces through southern Mexico and western Central America. They are also found in Florida and many Caribbean islands. In South America, they are patchy in the northwest and through the Andes, but widely distributed from southern Brazil to Patagonia and Tierra del Fuego. Burrowing owls are year-round residents in most of their range. Birds that breed in Canada and the northern U.S. usually migrate south to Mexico and the southern U.S. during winter months.


This species can live for at least 9 years in the wild and over 10 years in captivity. They are often killed by vehicles when crossing roads, and have many natural enemies, including badgers, coyotes, and snakes. They are also killed by both feral and domestic cats and dogs. Two birds studied in the Parque Nacional de La Macarena of Colombia were free of blood parasites.
Burrowing owls often nest and roost in the burrows made by ground squirrels, a strategy also used by rattlesnakes. When threatened, the owl retreats to the burrow and produces rattling and hissing sounds similar to those of a rattlesnake. The behavior is suggested to be an example of acoustic Batesian mimicry and has been observed to be an effective strategy against animals that are familiar with the dangers posed by rattlesnakes.


The nesting season begins in late March or April in North America. Burrowing owls usually only have one mate but occasionally a male will have two mates. Pairs of owls will sometimes nest in loose colonies. Their typical breeding habitat is open grassland or prairie, but they can occasionally adapt to other open areas like airports, golf courses, and agricultural fields. Burrowing owls are slightly tolerant of human presence, often nesting near roads, farms, homes, and regularly maintained irrigation canals.
The owls nest in a burrow, hence the name burrowing owl. If burrows are unavailable and the soil is not hard or rocky, the owls may excavate their own. Burrowing owls will also nest in shallow, underground, man-made structures that have easy access to the surface.
During the nesting season, burrowing owls will collect a wide variety of materials to line their nest, some of which are left around the entrance to the burrow. The most common material is mammal dung, usually from cattle. At one time it was thought that the dung helped to mask the scent of the juvenile owls, but researchers now believe the dung helps to control the microclimate inside the burrow and to attract insects, which the owls may eat.
The female lays an egg every one or two days until she has completed a clutch, which can consist of four to 12 eggs (usually 9). She then incubates the eggs for 3–4 weeks while the male brings her food. After the eggs hatch, both parents feed the chicks. Four weeks after hatching, the chicks can make short flights and begin leaving the nest burrow. The parents still help feed the chicks for 1–3 months.
Site fidelity rates appear to vary among populations. In some locations, owls will frequently reuse a nest several years in a row. Owls in migratory northern populations are less likely to return to the same burrow every year. Also, as with many other birds, the female owls are more likely to disperse to a different site than are male owls.


When hunting, they wait on a perch until they spot prey. Then, they swoop down on prey or fly up to catch insects in flight. Sometimes, they chase prey on foot across the ground. The highly variable diet includes invertebrates and small vertebrates, which make up roughly one-third and two-thirds of the diet, respectively. Burrowing owls mainly eat large insects and small rodents. Although burrowing owls often live close to ground squirrels (Marmotini), they rarely prey upon them.
Rodent prey is usually dominated by locally superabundant species, like the delicate vesper mouse (Calomys tener) in southern Brazil. Among squamates and amphibians, small lizards like the tropical house gecko (Hemidactylus mabouia), and frogs and toads predominate. Generally, most vertebrate prey is in the weight class of several grams per individual. The largest prey are usually birds, such as eared doves (Zenaida auriculata) which may weigh almost as much as a burrowing owl.
Regarding invertebrates, the burrowing owl seems less of a generalist. It is extremely fond of termites such as Termitidae, and Orthoptera such as Conocephalinae and Copiphorinae katydids, Jerusalem crickets (Stenopelmatidae) and true crickets (Gryllidae). Bothynus and Dichotomius anaglypticus scarab beetles (Scarabaeidae) were eaten far more often than even closely related species by many burrowing owls across central São Paulo (Brazil). Similarly, it was noted that among scorpions Bothriuridae were much preferred, among spiders Lycosidae (wolf spiders), and among millipedes (Diplopoda) certain Diplocheta. Small ground beetles (Carabidae) are eaten in quantity, while larger ones are much less popular as burrowing owl food, perhaps due to the vigorous defense the large species can put up. Burrowing owls are also known to place the fecal matter of large herbivorous mammals around the outside of their burrows to attract dung beetles, which are used to provide a steady source of food for the owls. Burrowing owls can also predate on invertebrates attracted to artificial night lighting.
Unlike other owls, they also eat fruits and seeds, especially the fruit of tasajillo (Cylindropuntia leptocaulis) and other prickly pear and cholla cacti. On Clarion Island, where mammalian prey is lacking, they feed essentially on crickets and prickly pear fruit, adding Clarión wrens (Troglodytes tanneri) and young Clarion mourning doves (Zenaida macroura clarionensis) on occasion.


The burrowing owl is endangered in Canada and threatened in Mexico. It is a state threatened species in Colorado and Florida and a California species of special concern. It is common and widespread in open regions of many Neotropical countries, where they sometimes even inhabit fields and parks in cities. In regions bordering the Amazon Rainforest they are spreading with deforestation. It is therefore listed as Least Concern on the IUCN Red List. Burrowing owls are protected under the Migratory Bird Treaty Act in Canada, the United States, and Mexico. They are also included in CITES Appendix II.


The major reasons for declining populations in North America are loss of habitat, and control programs for prairie dogs. While some species of burrowing owl can dig their own burrows, most species rely on burrowing animals to burrow holes that the owls can use as shelter and nesting space. There is a high correlation between the location of burrowing animal colonies, like those of ground squirrels, with the presence of burrowing owls. Rates of burrowing owl decline have also been shown to correlate with prairie dog decline. Western burrowing owls, for example, nest in burrows made by black-tailed prairie dogs since they are unable to dig their own. However, prairie dog populations have experienced a decline, one of the causes of this being prairie dog eradication programs. When prairie dogs dig burrows, they can uproot plants in the process. This is most common in agricultural areas, where burrows cause damage to existing crops, creating a problem for local farmers. In Nebraska and Montana, eradication programs have already been put in place to manage the population of prairie dogs. Eradication programs for ground squirrels have also been put in place. In California, California ground squirrels have been known to feed on crop seedlings as well as grasses meant for cattle, which prevents crop growth and decreases food supply for cattle. However, as burrowing animal populations decrease, burrowing owls become more vulnerable to exposure to predators. With fewer burrows available, burrowing owl populations will be more concentrated, with more owls occupying fewer burrows . As a result, predators will more easily detect owl populations and be capable of eliminating larger broods of owls at once. Prairie dogs and ground squirrels also act as a buffer between owls and their predators, since they become the target prey rather than the owls. Another benefit prairie dogs in particular provide burrowing owls takes the form of their alarm calls, which alert burrowing owls if predators are nearby, therefore giving the owls ample time to hide or escape. Without burrowing animals, almost every aspect contributing to suitable and safe living for burrowing owls will no longer be available. Organizations have tried contributing to the conservation of burrowing owls by digging artificial burrows for these owls to occupy in areas with no active colony of burrowing animals. However, creating artificial burrows is not sustainable and is not effective as a long term solution.


Burrowing owls readily inhabit some anthropogenic landscapes, such as airport grasslands or golf courses, and are known to take advantage of artificial nest sites (plastic burrows with tubing for the entrance) and perches. Burrowing owls have demonstrated similar reproductive success in rural grasslands and urban settings. The urban-residing burrowing owls have also developed the behavior of digging their own burrows and exhibit different fear responses to human and domestic dogs compared to their rural counterparts. Research has suggested that this species has made adaptations to the rapid urbanization of their usual habitat, and conservation efforts should be considered accordingly. Genetic analysis of the two North American subspecies indicates that inbreeding is not a problem within those populations.


Where the presence of burrowing owls conflicts with development interests, a passive relocation technique has been applied successfully: rather than capturing the birds and transporting them to a new site (which may be stressful and prone to failure), the owls are half-coerced, half-enticed to move on their own accord. The preparations need to start several months prior to the anticipated disturbance with observing the owl colony and noting especially their local movements and site preferences. After choosing a location nearby that has suitable ground and provides good burrowing owl breeding habitat, this new site is enhanced by adding burrows, perches, etc. Once the owls have accustomed to the changes and are found to be interested in the location – if possible, this should be at the onset of spring, before the breeding season starts – they are prevented from entering the old burrows. A simple one-way trapdoor design has been described that is placed over the burrow for this purpose. If everything has been correctly prepared, the owl colony will move over to the new site in the course of a few nights at most. It will need to be monitored occasionally for the following months or until the major human construction nearby has ended.


The little owl (Athene noctua), also known as the owl of Athena or owl of Minerva, is a bird that inhabits much of the temperate and warmer parts of Europe, the Palearctic east to Korea, and North Africa. It was introduced into Britain at the end of the 19th century and into the South Island of New Zealand in the early 20th century.
This owl is a member of the typical or true owl family Strigidae, which contains most species of owl, the other grouping being the barn owls, Tytonidae. It is a small, cryptically coloured, mainly nocturnal species and is found in a range of habitats including farmland, woodland fringes, steppes and semi-deserts. It feeds on insects, earthworms, other invertebrates and small vertebrates. Males hold territories which they defend against intruders. This owl is a cavity nester and a clutch of about four eggs is laid in spring. The female does the incubation and the male brings food to the nest, first for the female and later for the newly hatched young. As the chicks grow, both parents hunt and bring them food, and the chicks leave the nest at about seven weeks of age.
Being a common species with a wide range and large total population, the International Union for Conservation of Nature has assessed its conservation status as "least concern".


The little owl was formally described in 1769 by the Austrian naturalist Giovanni Antonio Scopoli under the binomial name Strix noctua. The little owl is now placed in the genus Athene that was introduced by the German zoologist Friedrich Boie in 1822. The owl was designated as the type species of the genus by the George Robert Gray in 1841.  The genus name, Athene, commemorates the goddess, whose original role as a goddess of the night might explain the link to an owl. The species name noctua has, in effect, the same meaning, being the Latin name of an owl sacred to Minerva, Athena's Roman counterpart.
Thirteen subspecies are recognised:
A. n. vidalii Brehm, AE, 1857 – west Europe
A. n. noctua (Scopoli, 1769) – central, south, southeast Europe to northwest Russia
A. n. indigena Brehm, CL, 1855 – Romania to Greece through Ukraine and Turkey east to south Russia
A. n. lilith Hartert, E, 1913 – Cyprus, south Turkey to Iraq and the Sinai (Egypt)
A. n. bactriana Blyth, 1847 – Iraq and Azerbaijan to Pakistan and northwest India
A. n. orientalis Severtsov, 1873 – northeast Kazakhstan and northwest China
A. n. ludlowi Baker, ECS, 1926 – Himalayas
A. n. impasta Bangs & Peters, JL, 1928 – west-central China
A. n. plumipes Swinhoe, 1870 – Mongolia, south-central Siberia and northeast China
A. n. glaux (Savigny, 1809) – coastal north Africa to southwest Israel
A. n. saharae (Kleinschmidt, 1909) – Morocco to west Egypt and central Arabia
A. n. spilogastra Heuglin, 1863 – east Sudan, Eritrea and northeast Ethiopia
A. n. somaliensis Reichenow, 1905 – east Ethiopia and Somalia


The little owl is a small owl with a flat-topped head, a plump, compact body and a short tail. The facial disc is flattened above the eyes giving the bird a frowning expression. The plumage is greyish-brown, spotted, streaked and barred with white. The underparts are pale and streaked with darker colour. It is usually 22 centimetres (8.7 in) in length with a wingspan of 56 centimetres (22 in) for both sexes, and weighs about 180 grams (6.3 oz).
The adult little owl of the most widespread form, the nominate A. n. noctua, is white-speckled brown above, and brown-streaked white below. It has a large head, long legs, and yellow eyes, and its white “eyebrows” give it a stern expression. Juveniles are duller, and lack the adult's white crown spots. This species has a bounding flight like a woodpecker. Moult begins in July and continues to November, with male starting before female.
The call is a querulous kiew, kiew. Less frequently, various whistling or trilling calls are uttered. In the breeding season, other more modulated calls are made, and a pair may call in duet. Various yelping, chattering or barking sounds are made in the vicinity of the nest.


This owl usually perches in an elevated position ready to swoop down on any small creature it notices. It feeds on prey such as insects and earthworms, as well as small vertebrates including amphibians, reptiles, birds and mammals. It may pursue prey on the ground and it caches surplus food in holes or other hiding places. A study of the pellets of indigestible material that the birds regurgitate found mammals formed 20 to 50% of the diet and insects 24 to 49%. Mammals taken included mice, rats, voles, shrews, moles and rabbits. The birds were mostly taken during the breeding season and were often fledglings, and including the chicks of game birds. The insects included Diptera, Dermaptera, Coleoptera, Lepidoptera and Hymenoptera. Some vegetable matter (up to 5%) was included in the diet and may have been ingested incidentally.
The little owl is territorial, the male normally remaining in one territory for life. However the boundaries may expand and contract, being largest in the courtship season in spring. The home range, in which the bird actually hunts for food, varies with the type of habitat and time of year. Little owls with home-ranges that incorporate a high diversity of habitats are much smaller (< 2 ha) than those which breed in monotonous farmland (with home-ranges over 12 ha).  Larger home ranges results in increased flight activity, longer foraging trips and fewer nest visits.  If a male intrudes into the territory of another, the occupier approaches and emits its territorial calls. If the intruder persists, the occupier flies at him aggressively. If this is unsuccessful, the occupier repeats the attack, this time trying to make contact with his claws. In retreat, an owl often drops to the ground and makes a low-level escape. The territory is more actively defended against a strange male as compared to a known male from a neighbouring territory; it has been shown that the little owl can recognise familiar birds by voice.
The little owl is partly diurnal and often perches boldly and prominently during the day. If living in an area with a large amount of human activity, little owls may grow used to humans and will remain on their perch, often in full view, while people are around. The little owl has a life expectancy of about 16 years. However, many birds do not reach maturity; severe winters can take their toll and some birds are killed by road vehicles at night, so the average lifespan may be on the order of 3 years.


A. noctua has an extremely large range. It has been estimated that there are between 560 thousand and 1.3 million breeding pairs in Europe, and as Europe equates to 25 to 49% of the global range, the world population may be between 5 million and 15 million birds. The population is believed to be stable, and for these reasons, the International Union for Conservation of Nature has assessed the bird's conservation status as being of "least concern".