Adiantum villosum Linnaeus, Syst. nat. ed. 10, 2: 1328. 1759.

Neotype. Sloane, vol. J, p. 127, from nr. Spanish Town, Jamaica (BM-SL), designated by Proc. tor, 1977. Illustrated by Sloane, Nat. Hist. Jamaica 1: t. 55, fig. 1.

Syn. Adiantum falcatum Swartz, J. Bot. (Schrader) 1800(2): 82. 1802. (Lectotype. Sloane, Nat. Hist. Jamaica 1: t. 55, fig. 1.)

Rhizome creeping, subwoody, 4-6 mm thick, nodose, clothed at apex with dark brown, subclathrate, denticulate, narrowly deltate-attenuate scales 1.5-2.5 mm long. Fronds closely distichous, stiffly ascending, 50-85(-100) cm long; stipes lustrous purple-black, angulate, 35-55 cm long, 2-4 mm in diam. near base, deciduously clothed with brown, loosely appressed, narrowly linear scales, these laxly long-ciliate at base and denticulate-ciliate along margins. Blades ovate or (excluding the elongate terminal pinna) transversely oblong, 25-40 cm long, 25-50 cm broad, uniformly 2-pinnate; rhachis and costae more or less densely clothed with narrow ciliate or denticulate scales like those of stipe; lateral pinnae 2-6 pairs, alternate, spreading, lance-oblong to linear and up to 25 cm long; pinnules 1.5-2.5 (-4) cm long, 0.6-1 cm broad; sterile pinnules sharply biserrate; fertile pinnules more or less rhombic-oblong with abruptly acute or acuminate tips, quadrangular at base, almost dimidiate, a faint costule present near basiscopic side; tissue medium green, firmly herbaceous. Sori borne along acroscopic margin of pinnules and around the tip, normally continuous, or sometimes interrupted and arcuate; indusioid flap light brown, the margin. erose.

General Distribution. Greater and Lesser Antilles, and continental tropical America from Mexico to northern South America.

Distribution in Puerto Rico. No specilllen seen from the m1ain island; recorded from Vieques. Virgin Islands. St. Croix and St. Thomas.

Habitat. Shaded rocky banks and wooded hillsides at lower middle elevations ( 120-300 m), rare or locally frequent.