Asplenium scolopendrium var. americanum (Fernald) Kartesz & Gandhi
Descripción
Roots coarse, fibrous, not proliferous; rhizomes erect; rhizome scales blackish to dark brown, clathrate, 1.5–6 X 1–1.5 mm, entire or weakly short-ciliate; fronds clumped, 9–65 cm long; stipes brownish to stramineous, dull, 1.5–20 cm X 1.5–5 mm, ca. 1⁄5–1⁄3 of frond length, with dense, linear to lanceolate, tan, ultimately clathrate scales, not alate; blades thick-herbaceous to subcoriaceous, simple, 7–22(–35) X 1.8–5 cm, oblong, entire to slightly undulate, bases cordate to subcordate or with two downward-directed lobes, apices acute, proliferous buds absent; rachises brownish at bases, light green to stramineous distally (lighter than the blades), dull, with sparse to dense scales 1–2.5 X 0.1–0.2 mm, not winged; pinnae absent; veins simple or 1- or 2-forked, obscure, parallel for most of their length, tips evident adaxially; indument abaxially of scattered, linear scales to 0.5–1 X 0.1 mm, also with sparse catenate hairs to 0.5 mm long; sori paired, facing each other on adjacent veins, usually confined to distal 1⁄2–2⁄3 of blades; indusia (2–)6–15 X 0.3–0.7 mm, margins entire or repand; spores reniform; 2n=144 (Can, USA, Chis, see Viane & Reichstein, 1991: 163).A
Forma de vida
Epífita or epipetricA
Ejemplar revisado
Chis (Fraser-Jenkins 13213, UC; García F. 567, XAL; Ghiesbreght 296, K, 307, K, NY, PH; Münch 80, DS). NL (Favela L. 210, 215, ENCB, 212, ANSM). Oax (Mickel 5385, NY).
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Elevación
2100–2200 mA
Ecología y Hábitat
Epipetric on moist calcareous rocks (dolomitic limestone) in sinkholes, at cave entrances, and on cool, moist talus, and on limestone cliffs, occasionally epiphytic on old oaks, in deep shade.A
Tipo de vegetación
Bosque de encinoA
Categoría IUCN
No incluidaC
Categoría NOM-059-SEMARNAT-2010
No incluidaD
Discusión taxonómica
Asplenium scolopendrium var. americanum is extremely rare in Mexico. Plants from southern Mexico have been called Phyllitis lindenii, or Asplenium scolopendrium var. lindenii, which supposedly differs from the eastern North American var. americanum in the less prominently cordate blade bases and more abundantly scaly stipes and rachises. These differences seem part of the normal variation of the species, and the scale difference is probably a function of age of fronds and state of preservation. Specimens from Chiapas have their blade bases exactly like those from further north. Apparently, the two varieties do not differ in chromosome number, as previously supposed (see Viane & Reichstein, 1991). The chromosome count by Löve and Löve (1973) of n=36 is very likely erroneous (no voucher exists; Brouillet, pers. comm.). Asplenium scolopendrium L. var. scolopendrium [Sp. Pl. 2: 1079. 1753. Phyllitis scolopendrium (L.) Newman, Hist. Brit. Ferns, ed. 2, 10. 1844. Type. Europe (LINN)] occurs in Europe, Macaronesia, and western Asia. The East Asian variant of Asplenium scolopendrium, also tetraploid, is sometimes considered a separate species Phyllitis japonica Kom. or Asplenium komarovii Akasawa, but it seems only weakly, if at all, separable.A