Nephrolepis
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Authority
Mickel, John T. & Smith, Alan R. 2004. The pteridophytes of Mexico. Mem. New York Bot. Gard. 88: 1-1054.
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Family
Nephrolepidaceae
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Scientific Name
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Description
Genus Description - Terrestrial, on rocks, or epiphytic; rhizomes decumbent or commonly erect, weakly developed, dictyostelic, perennial to probably annual, scaly at the apices, usually stoloniferous, with stolons mostly aboveground and wiry, sometimes producing young plants along their length, a few species bearing underground, perennating tubers; fronds clumped in a tight cluster, erect to arching to pendent in some species, monomorphic, polystichous, non-articulate, medium-sized to large; stipes short, scaly to glabrescent, stramineous to brown; blades 1-pinnate, slowly determinate to seemingly indeterminate with a loose bud formed of undeveloped pinnae at each blade apex, glabrous, hairy, or with lanceolate scales; pinnae numerous, thin to subcoriaceous, entire or shallowly lobed to serrulate or crenulate, sometimes auriculate at the superior base, inequilateral with greater development on acroscopic side, articulate to rachises, often with lime-dotted hydathodes on vein tips adaxially; veins free, 1-4-forked; sori terminal on the veins, sometimes confined to the distal pinnae, medial to often supramedial or submarginal, round to slightly elongate, uniseriate along both sides of costae, lacking paraphyses; indusia persistent, round to semicircular or reniform (lunate), entire; spores ellipsoid, bilateral, perispores rugose to tuberculate; x = 41.
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Discussion
Lectotype: Uncertain, regarded by J. Smith (Hist. Fil. 226. 1875) and R. Tryon (Contr. Gray Herb. 194: 225. 1964) as Nephrolepis exaltata (L.) Schott, but by Christensen (Index Filic. XXVII. 1906) as N. biserrata (Sw.) Schott.
Nephrolepis is a genus of 20–25 species of tropical regions of the world, 7 native in America, one species naturalized from Asia. The genus is very distinctive, distinguished by the wiry stolons, linear, 1-pinnate fronds, and articulate pinnae. It is sometimes placed in its own family, Nephrolepidaceae; by others, it is placed in Davalliaceae or Dryopteridaceae. In molecular analyses, Nephrolepis is imbedded within a large group of dryopteroid genera, but the exact relationships are still uncertain (Hasebe et al., 1995). Numerous cultivars exist within several of the native and naturalized species. These are discussed under the appropriate species below. One additional cultivar, not known to have escaped in Mexico, is often also grown in many cities: Nephrolepis falcata (Cav.) C. Chr. cv. Furcans, represented by specimens from Veracruz (Nevling & Go´mez-Pompa 297, MEXU) and Guerrero (Calzada & Salinas 17700, UAMIZ); we have seen it growing in the city of Xalapa, and also in Veracruz, and Magan˜a (1992) cited it from Tabasco. This species is believed to be native to Malesia and Polynesia. The cultivar can be readily recognized by the rather large, usually 1-forked pinnae, and hence has the common name “Fishtail fern.”