Nephrolepis
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Authority
Proctor, George R. 1989. Ferns of Puerto Rico and the Virgin Islands. Mem. New York Bot. Gard. 53: 1-389.
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Family
Nephrolepidaceae
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Scientific Name
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Type
Type Species. Nephrolepis exaltata (Linnaeus) Schott, based on Polypodium exaltatum Linnaeus of the Bahamas, Greater Antilles, and adjacent continental areas.
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Description
Species Description - Medium-sized terrestrial or epiphytic fems, or sometimes on rocks. Rhizomes erect and short, sometimes decumbent, densely clothed with scales, and usually proliferating by means of elongate slender stolons, rarely geophytic or producing underground tubers. Fronds clustered, crowded, not articulate to the rhizome, stipitate, the stipes usually short. Blades linear to linear-oblong, normally 1-pinnate (but variously more dissected forms are common in horticulture), the apex often appearing to be of indeterminate growth; pinnae numerous, articulate to the rhachis and eventually deciduous; veins free, 1- to 4-branched, all but the fertile ones reaching nearly to the margins, with ends thickened and often secreting a small white scale of calcium carbonate on the adaxial side. Sori usually terminal on the first distal vein branches, medial to submarginal (or in one Old World species, N. acutifolia (Desvaux) Christ, elongate on a vascular commissure connecting the vein tips in a single row on either side of the costa; indusium lunate to orbicular, attached at the sinus (or, in N. acutifolia, a linear indusium); paraphyses absent; spores ellipsoid, monolete, the surface irregularly tuberculate to rugose.
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Discussion
A pantropical genus of more than 20 species, the names of some of them often confused; the natural distribution of several species has been blurred by extensive cultivation and widespread naturalization. Puerto Rico is here credited with five indigenous species and several others that have escaped from cultivation. This genus is the most important fem group in the Puerto Rican horticultural trade. The generic name is derived from the Greek nephros, kidney + lepis, scale, alluding to the indusium-shape ofthe type species.
Special Literature. Morton, C. V. 1958. Observations on cuhivated fems, V. The species and forms of Nephrolepis. Amer. Fem J. 48: 18-27; Stolze, R. G. 1981. Nephrolepis, in Fems of Guatemala, Fieldiana: Bot. n.s. 6: 310-317; Tryon, R. M . & A. F. Tryon. 1982. Fems and allied plants, pp. 656-662, 15 figs.