Adiantum trapeziforme L.
Descripción
Rhizomes short- to long-creeping, 3–5 mm diam.; rhizome scales bicolorous, light brown at bases to lustrous dark brown at tips, linear-lanceolate, denticulate, 2–3 X 0.1–0.3 mm; fronds distant, (40–)60–100 cm long, arching; stipes atropurpureous to blackish, lustrous, 35–60 cm X 4–6 mm, nearly 1⁄2 the frond length, glabrous except at bases, with minute tubercles; blades broadly ovate, 3–4-pinnate proximally, 2-pinnate distally, each blade with a conform, 1-pinnate terminal pinna; rachises atropurpureous, glabrous; pinnae 3–4 compound pairs, the proximal pair the longest, 25–35 X ca. 15 cm; pinnulets mostly trapeziform, inequilateral, (20–)35–50 X 10–20 cm, acute to acuminate at tips, sterile margins incised-lobate, fertile margins only shallowly so, stalked 1–5 mm, articulate, stalk color ending abruptly at pinnulet bases, articulate; veins free, forking, ending in teeth at the margins; indument absent on both blade surfaces, blades sometimes glaucous abaxially; idioblasts absent; sori 10–15 along acroscopic margins of pinnules, 1–2 per lobe, also 3–5 along distal margins; indusia 1–3 mm long; oblong, glabrous; 2n=60, 90 (cult).A
Forma de vida
TerrestreA
Ejemplar revisado
Chis (Davidse et al. 30135, MO, NY). Gro (Palmer 519, B, NY). Hgo (Gimate 833, CAS, ENCB). Jal (Dieterle 4056, CAS, ENCB, IEB, MICH). Méx (Hinton 7644, NY). Mich (Hinton 12277, NY). Nay (McVaugh 18799, IEB, NY). NL (Rodríguez s.n., 22 Apr 1979, ANSM, ENCB, UNL). Oax (Hallberg 1263, ENCB, NY). Pue (Segura A. 16, FCME). Qro (Rzedowski 42804, ENCB, IEB). SLP (Pringle 3960, B, BR, CAS, ENCB, NY, P). Tam (Palmer 303, B, NY). Ver (Calzada 917, ENCB, MEXU, MO, XAL). Unverified, Doubtful, or Mistaken Reports. Tab (reported by Magaña, 1992, but not verified).A
Elevación
50 – 900 mA
Ecología y Hábitat
In wet forests at lower elevations.A
Categoría IUCN
No incluidaB
Categoría NOM-059-SEMARNAT-2010
No incluidaC
Discusión taxonómica
Among the tripinnate species with a conform terminal pinna, A. trapeziforme is distinctive in its glabrous stipes, rachises and pinnulets, articulate pinnulets, and lack of epidermal idioblasts. South American material has been ascribed to this species; some of these specimens, especially from Peru, Bolivia, and Brazil, have been named A. mathewsianum Hook., which is certainly very closely related to A. trapeziforme. Additionally, true A. trapeziforme may be naturalized in South America, as it seems to be in Paraguay and in areas of Asia and the Pacific. Further study is needed.A