Adiantum shepherdii Hook.
Descripción
Rhizomes short-creeping, compact, 3–6 mm diam.; rhizome scales golden brown, linear-lanceolate, 2–3 X 0.3–0.5 mm, sparsely ciliate-denticulate; fronds clumped, 20–46 cm long, arching; stipes castaneous to atropurpureous, 2–6(–15) cm X 1–2 mm, 1⁄10–1⁄5 the frond length, glabrous except at bases; blades linear, 1-pinnate, 2–3.5 cm wide, infrequently 2-pinnate at the bases; rachises castaneous or red-brown, glabrous; pinnae 34–56 pairs, to 1.7 X 1 cm, alternate, very gradually reduced toward the blade apices, sessile, obliquely flabellate or dimidiate, bases often overlapping the rachises, sterile margins entire to broadly crenate, distinctly thickened; pinnules absent on pinnae, except infrequently on the proximal pair, those sometimes 1-pinnate, to 15 X 2 cm with up to 15 pinnules, non-articulate; veins free, forking, ending at the cartilaginous margins; indument absent on both blade surfaces; idioblasts absent; sori 3–6 per pinna, confined to acroscopic and distal margins; indusia 1–2 mm long and wide, round-reniform and with deep sinuses, glabrous.A
Forma de vida
TerrestreA
Ejemplar revisado
Gro (Hinton 11347, DS, MEXU; Langlassé 322, MEXU, US; Mexia 8804, B, CAS, NY, UC, US). Méx (Hinton 1602, MEXU, 4758, K, US; Matuda 31053, MEXU, UC, US). Mich (Hinton 13485, ENCB, NY, US; King & Soderstrom 4806, MEXU, UC; Rzedowski 51698, IEB, MEXU; Ventura 2484, ENCB, NY).A
Distribución
México (país) EndémicoA
Elevación
400 – 1850(– 2200) mA
Ecología y Hábitat
On rocky banks.A
Tipo de vegetación
Bosque de encino, Bosque de pino-encinoA
Categoría IUCN
No incluidaB
Categoría NOM-059-SEMARNAT-2010
No incluidaC
Discusión taxonómica
This species is characterized by the linear fronds with many pairs of strongly overlapping and very gradually reduced distal pinnae at the almost indeterminate blade apices. The closest relatives are A. galeottianum and A. patens, which occur in the same general area. Adiantum shepherdii is a relatively rare endemic at middle elevations in western Mexico.A