Asplenium platyneuron, commonly known as ebony spleenwort or brownstem spleenwort, is a fern native to North America east of the Rocky Mountains. It takes its common name from its dark, reddish-brown, glossy stipe and rachis, which support a once-divided, pinnate leaf. The fertile fronds, which die off in the winter, are darker green and stand upright, while the sterile fronds are evergreen and lie flat on the ground. An auricle at the base of each pinna points towards the tip of the frond. The dimorphic fronds and alternate, rather than opposite, pinnae distinguish it from the similar black-stemmed spleenwort.
Dryopteris marginalis, vernacularly known as the marginal shield fern or marginal wood fern, is a perennial species of fern found in damp shady areas throughout eastern North America, from Texas to Minnesota and Newfoundland. It favors moderately acid to circumneutral soils in cooler areas but is fairly drought-resistant once established. In the warmer parts of its range, it is most likely to be found on north-facing non-calcareous rock faces. It is common in many altitudes throughout its range, from high ledges to rocky slopes and stream banks. Marginal wood fern's name derives from the fact that the sori are located on the margins, or edges of the leaflets.
Polystichum acrostichoides, commonly denominated Christmas fern, is a perennial, evergreen fern native to eastern North America, from Nova Scotia west to Minnesota and south to Florida and eastern Texas. It is one of the most common ferns in eastern North America, being found in moist and shady habitats in woodlands, stream banks and rocky slopes. The common name derives from the evergreen fronds, which are often still green at Christmas.
Asplenium septentrionale is a species of fern known by the common names northern spleenwort and forked spleenwort. It is native to Europe, Asia and western North America, where it grows on rocks. Its long, slender leaves give it a distinctive appearance. Three subspecies exist, corresponding to a tetraploid and a diploid cytotype and their triploid hybrid.
Dryopteris intermedia, the intermediate wood fern or evergreen wood fern, is a perennial, evergreen wood fern native to eastern North America. It is a diploid species, and is the parent of several species of hybrid origin, including Dryopteris carthusiana. Other common names for this species include intermediate shield fern, fancy wood fern, fancy fern, glandular wood fern, American shield fern and common wood fern.
Parathelypteris noveboracensis, synonym Thelypteris noveboracensis, the New York fern, is a perennial species of fern found throughout the eastern United States and Canada, from Louisiana to Newfoundland, but most concentrated within Appalachia and the Atlantic Northeast. New York ferns often forms spreading colonies within the forests they inhabit.
Asplenium pinnatifidum, commonly known as the lobed spleenwort or pinnatifid spleenwort, is a small fern found principally in the Appalachian Mountains and the Shawnee Hills, growing in rock crevices in moderately acid to subacid strata. Originally identified as a variety of walking fern, it was classified as a separate species by Thomas Nuttall in 1818. It is believed to have originated by chromosome doubling in a hybrid between walking fern and mountain spleenwort, producing a fertile tetraploid, a phenomenon known as alloploidy; however, the hypothesized parental hybrid has never been located. It is intermediate in morphology between the parent species: while its leaf blades are long and tapering like that of walking fern, the influence of mountain spleenwort means that the blades are lobed, rather than whole. A. pinnatifidum can itself form sterile hybrids with several other spleenworts.
Asplenium bradleyi, commonly known as Bradley's spleenwort or cliff spleenwort, is a rare epipetric fern of east-central North America. Named after Professor Frank Howe Bradley, who first collected it in Tennessee, it may be found infrequently throughout much of the Appalachian Mountains, the Ozarks, and the Ouachita Mountains, growing in small crevices on exposed sandstone cliffs. The species originated as a hybrid between mountain spleenwort and ebony spleenwort ; A. bradleyi originated when that sterile diploid hybrid underwent chromosome doubling to become a fertile tetraploid, a phenomenon known as allopolyploidy. Studies indicate that the present population of Bradley's spleenwort arose from several independent doublings of sterile diploid hybrids. A. bradleyi can also form sterile hybrids with several other spleenworts.
Deparia acrostichoides, commonly called silvery glade fern or silvery spleenwort, is a perennial species of fern. Its range include much of the eastern United States and Canada, from Ontario to Nova Scotia, and Georgia to Louisiana and eastern Asia in China, Russia, Japan and Korea. The name silvery comes from the fact that the indusia on the underside of the leaf have a silver color when the sori are close to ripening.
Asplenium × ebenoides is a hybrid fern native to eastern North America, part of the "Appalachian Asplenium complex" of related hybrids. The sterile offspring of the walking fern (A. rhizophyllum) and the ebony spleenwort (A. platyneuron), A. × ebenoides is intermediate in morphology between its two parents, combining the long, narrow blade of A. rhizophyllum with a dark stem and lobes or pinnae similar to those of A. platyneuron. While A. × ebenoides is generally sterile, fertile specimens with double the number of chromosomes are known from Havana Glen, Alabama. These fertile allotetraploids were reclassified as a separate species named A. tutwilerae in 2007, retaining the name A. × ebenoides for the sterile diploids only.
Asplenium resiliens, the blackstem spleenwort or little ebony spleenwort, is a species of fern native to the Western Hemisphere, ranging from the southern United States south to Uruguay, including parts of the Caribbean. Found on limestone substrates, it is named for its distinctive purplish-black stipe and rachis. A triploid, it is incapable of sexual reproduction and produces spores apogamously. First described by Martens and Galeotti in 1842 under the previously used name Asplenium parvulum, the species was given its current, valid name by Kunze in 1844. Several similar species are known from the tropics; A. resiliens may have arisen from these species by reticulate evolution, but precise relationships among the group are not yet certain.
Asplenium tutwilerae is a rare epipetric fern found only in Hale County, Alabama, United States. A. tutwilerae is a fertile allotetraploid, formed by the chromosomal doubling of a specimen of the sterile diploid A. × ebenoides, a hybrid of A. platyneuron and A. rhizophyllum. Except for its spores, which are fertile rather than malformed, A. tutwilerae is essentially identical to A. × ebenoides and was described as part of that species until 2007. It is named in honor of Julia Tutwiler, who discovered the only known wild population at Havana Glen in 1873.
Asplenium × gravesii, commonly known as Graves' spleenwort, is a rare, sterile, hybrid fern, named for Edward Willis Graves (1882–1936). It is formed by the crossing of Bradley's spleenwort (A. bradleyi) with lobed spleenwort (A. pinnatifidum). It is only found where its parent species are both present; in practice, this proves to be a few scattered sites in the Appalachian Mountains, Shawnee Hills, and Ozarks, reaching perhaps its greatest local abundance around Natural Bridge State Resort Park. Like its parents, it prefers to grow in acid soil in the crevices of sandstone cliffs.
Asplenium × trudellii, commonly known as Trudell's spleenwort, is a rare hybrid fern of the eastern United States, first described in 1925. It is formed by the crossing of mountain spleenwort (A. montanum) with lobed spleenwort (A. pinnatifidum). Trudell's spleenwort is intermediate in form between its two parents, and is generally found near them, growing on exposed outcrops of acidic rock. While A. × trudellii is triploid and sterile, there is some evidence that it can occasionally reproduce apogamously.
Asplenium × kentuckiense, commonly known as Kentucky spleenwort, is a rare, sterile, hybrid fern. It is formed by the crossing of lobed spleenwort (A. pinnatifidum) with ebony spleenwort (A. platyneuron). Found intermittently where the parent species grow together in the eastern United States, it typically grows on sandstone cliffs, but is known from other substrates as well.
Asplenium × boydstoniae, commonly known as Boydston's spleenwort, is a rare, sterile, hybrid fern. It is formed by the crossing of Tutwiler's spleenwort (A. tutwilerae) with ebony spleenwort (A. platyneuron). The hybrid was produced in culture in 1954. It was not discovered in the wild until 1971, when it was found by Kerry S. Walter at Havana Glen, Alabama, the only known wild site for Tutwiler's spleenwort. Walter named it for Kathryn E. Boydston, an expert in fern culture. Except for the tip of its leaf blade, it largely resembles its ebony spleenwort parent.
Asplenium arcanum is a fern known from western Mexico and Nicaragua.
Asplenium appendiculatum, ground spleenwort, is a common native fern to Australia and New Zealand. It usually grows in cool damp conditions, among rocks, on logs or as an epiphyte.
Myriopteris yatskievychiana is a small fern native to Mexico, a member of the family Pteridaceae. It is known only from a single collection in the Mexican state of Sonora. While superficially similar to golden lip fern, a widespread species in Mexico, differences in its coating of hairs and its small size make it distinctive. One of the cheilanthoid ferns, it was usually classified in the genus Cheilanthes until 2013, when the genus Myriopteris was again recognized as separate from Cheilanthes.
Anemia tabascana is a fern endemic to the state of Tabasco, Mexico. It grows on road banks on a single hill in Huimanguillo. Like other members of the genus, its leaves are pinnately divided into a single set of leaflets; in fertile leaves, the lowest pair of leaflets projects at right angles to the rest of the leaf and bears spores. The freely forking veins, which do not rejoin one another after forking, and sparse, rather than abundant, hairs on the leaf axes, distinguish it from similar species in the genus.
