Asplenium heterochroum Kunze
Descripción
Roots thin to filamentous, wiry, not proliferous; rhizomes erect; rhizome scales bicolorous, center strongly clathrate, margins lighter, lumina not occluded, ca. 1.5 X 0.3–0.5 mm, entire; fronds numerous, clumped, (5–)8–15(–35) cm long; stipes black, lustrous, 1–4(–7) cm X 0.3–1 mm, 1⁄10–1⁄5 of frond length, with hair-like scales ca. 2 X 0.1–0.2 mm long, adaxially with tan wings 0.1–0.2 mm wide; blades thin-chartaceous, linear, 1-pinnate, 7–12 cm X 7–18 mm, slightly narrowed proximally (sometimes nearly to the rhizomes), tapering at tips to confluent, sometimes ligulate terminal segments; rachises black, lustrous, glabrous, with tan wings ca. 0.1 mm wide on adaxial shoulders; pinnae oblong, 15–25(–45) pairs, 3–6 X 1.5–3(–4) mm, stalked to 0.2 mm, bases inequilateral, cuneate basiscopically, apices rounded to serrulate, acroscopic margins serrulate, sinuate-crenate, or subentire; veins simple to 1-forked, vein tips obscure adaxially; indument abaxially of whitish appressed clavate hairs 0.1 mm long; sori mostly 2–5 pairs per pinna, on both sides of midveins; indusia 0.5–1 X 0.3–0.5 mm, margins erose; spores reniform; 2n=144 (Fla).A
Forma de vida
TerrestreA
Ejemplar revisado
Chis (Breedlove 22379B, DS, 32911, DS, MEXU, 33216, DS; Sohns 1713, MEXU, US). Ver (Copeland herb. 67, BM).
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Elevación
200–1400 mA
Ecología y Hábitat
Epipetric on limestone rocks, or terrestrial in calcareous soils.A
Categoría IUCN
No incluidaC
Categoría NOM-059-SEMARNAT-2010
No incluidaD
Discusión taxonómica
Asplenium heterochroum is distinguishable from all the lustrous- and dark-stiped, 1-pinnate Aspleniums (except A. nesioticum, A. resiliens, and A. palmeri) by the lack of conspicuous hydathodes adaxially on the blades. The closest relative in Mexico, and perhaps elsewhere, is A. nesioticum, from which A. heterochroum differs by the thinner blade texture (veins readily visible by transmitted light) and more sharply crenate-dentate pinna margins (Maxon, 1913). The smaller, thinner, more dentate pinnae, more delicate, arching fronds without strongly deflexed pinnae, smaller rhizome scales (2 mm), and occurrence at lower elevations, distinguish A. heterochroum from A. resiliens (which see). The occurrence at lower elevations and lack of terminal buds on the blades distinguish A. heterochroum from A. palmeri (which see).
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