Asplenium septentrionale (L.) Hoffm.
Descripción
Roots filamentous, wiry, not proliferous; rhizomes erect, much branched to produce many-stemmed tufts or mats bearing numerous crowded fronds; rhizome scales dark reddish brown to black, clathrate, 2–4 X 0.2–0.4 mm, entire; fronds clumped, 2–12 cm long; stipes dark reddish brown proximally, greenish distally, dull, 2–11 cm X 0.2–0.3 mm, 2⁄3–9⁄10 of frond length, glabrous, not alate but with two thickened adaxial ridges; blades thick-herbaceous, linear, simple to 1-forked or lacerate at the tips, occasionally 1-pinnate with a single lateral pinna, mostly 0.5–2.5 X 0.1–0.2 cm for unforked blades, to 1 cm if the single pinna strongly diverges, glabrous, bases acute, apices acute, not rooting at tips; rachises green, dull, glabrous; pinnae commonly none or one per frond and then strongly ascending, linear, 5–10 X 0.75–2 mm, apices acute, margins entire to remotely lacerate; veins 1-forked or absent except for main midrib, obscure, tips not evident adaxially; indument not seen, blades appearing glabrous; sori usually 2+ per pinna, parallel to margins and facing each other; indusia whitish to tan, mostly 5–20 X 0.5 mm, margins entire to subentire; spores reniform, 64 per sporangium; 2n=144 (Europe).A
Ejemplar revisado
BCN (Brandegee s.n., 18 May 1893, DS, NY, UC, US; Moran & Thorne 14343, ENCB).A
Elevación
2200–3050 mA
Ecología y Hábitat
In volcanic and granitic rock crevices.A
Categoría IUCN
No incluidaC
Categoría NOM-059-SEMARNAT-2010
No incluidaD
Discusión taxonómica
Two subspecies are recognized in Europe (Reichstein, 1981); ours is subsp. septentrionale. Asplenium septentrionale is easily distinguished from all other spleenworts in Mexico by the linear, grass-like or distally 1-forked blades, with blade segments (or occasionally pinnae) only ca. 1–2 mm wide. Farther north in the range, in California, this rare species grows in holes or crevices of volcanic boulders, and that also appears to be the favored habitat in the Sierra San Pedro Mártir, the only area where it is known in Mexico.A