Asplenium nesioticum Maxon
Descripción
Roots filamentous, fibrous, not proliferous; rhizomes suberect; rhizome scales black, 1.5–2 X 0.2–0.3 mm, lumina occluded; fronds clumped, 6–15(–22) cm long; stipes blackish, 0.5–1(–4) cm X 0.5–1 mm, less than 1⁄10 of frond length, glabrous, adaxially with whitish wings 0.1 mm wide; blades thick-chartaceous, 5–15(–20) X 1.5–2 cm, 1-pinnate, narrowly elliptic-linear, proximal 4–5 pairs of pinnae reduced nearly to rhizomes, dwindling slightly at tips to confluent, sometimes hastate terminal segments; rachises atropurpureous, lustrous, glabrous, adaxially with narrow whitish wings 0.1–0.2 mm wide; pinnae oblong, 15–20(–30) pairs, 7–10 X 2–4 mm, dimidiate, sometimes with small basal acroscopic auricles, apices obtuse, serrulate to crenulate-dentate along acroscopic margins and tips; veins mostly simple, obscure on both surfaces of pinnae, tips not evident adaxially; indument abaxially of scattered, appressed to spreading, whitish hairs 0.1 mm long on veins and tissue between veins; sori (1–)2–5 pairs per pinna, on both sides of midveins; indusia whitish, 1–2 X 0.3–0.4 mm, margins erose; spores ovoid-globose, 32 per sporangium (Purpus 4880, UC), or reniform, 64 per sporangium (see below).A
Ejemplar revisado
DF (Schaffner 70, 109, NY). Gto (Correll & Correll 28819, LL p.p.). NL (Webster & Preston 2885, TEX). SLP ( Purpus 4880, UC, US, 5487, UC).
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Elevación
1350–2100 mA
Ecología y Hábitat
Presumably on rocks (pedregal) and ledges.A
Categoría IUCN
No incluidaC
Categoría NOM-059-SEMARNAT-2010
No incluidaD
Discusión taxonómica
Specimens of this species from Mexico have previously been determined as A. heterochroum, A. palmeri, and A. aff. resiliens, all of which are closely related. Asplenium nesioticum differs from A. heterochroum in having thicker blade texture (veins not visible), shorter stipes, and less sharply crenate-dentate pinna margins. From A. resiliens, A. nesioticum differs in having inframedial to medial sori, thinner blade texture, and acuminate (vs. hairlike) scale tips. From A. palmeri, A. nesioticum differs in lacking proliferous blade tips. Webster & Preston 2885, from Nuevo Leon, was annotated by Wendt as Asplenium aff. resiliens, “but sexual, 64 spores/sporangium.” We confirm this number, and suggest that this species may be one of the sexual progenitors of the apogamous A. resiliens, 2n=108 with 32 large spores per sporangium. Further work is needed on this difficult complex of anhydathodous spleenworts of the A. trichomanes group.A