Asplenium exiguum Bedd.
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Authority
Mickel, John T. & Smith, Alan R. 2004. The pteridophytes of Mexico. Mem. New York Bot. Gard. 88: 1-1054.
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Family
Aspleniaceae
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Scientific Name
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Description
Species Description - Roots fibrous, not proliferous; rhizomes short-creeping or erect; rhizome scales black, clathrate with occluded lumina, 2.5–3 x 0.5–0.8 mm, entire or nearly so; fronds clumped, 6–18 cm long; stipes castaneous, or sometimes darkened only at the base, 1–5 cm x 0.4–1 mm, 1/10–1/8 of frond length, sparsely scaly, the scales hair-like or lanceolate, not winged; blades 5–14 x 1.5–2.5(– 3.5) cm, narrowly elliptic, 1–2-pinnate-pinnatifid, proximal pinnae gradually reduced, the apices sometimes proliferous, flagelliform; rachises brown proximally, greenish distally, with scattered hair-like scales 1–3 mm long, not winged; pinnae 10–18 pairs, 6–16 x 5–9 mm, apices emarginate, each with a proproliferous bud, the buds usually dormant and developing further only in very moist situations, pinnules oblong, subentire to toothed, each one sometimes with a bud at the tip; veins obscure, tips not evident adaxially; indument abaxially of scattered whitish to tan clavate hairs 0.1 mm long; sori to ca. 15 per pinna, on both sides of costae, 1–2(–4) per pinnule; indusia whitish, 1–1.5 x 0.3–0.5 mm, margins suberose to erose; spores reniform; 2n=144 (India).
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Discussion
Type. India. Nilgris, Beddome s.n. (K!).
Athyrium gracile E. Fourn., Mexic. Pl. 1: 102. 1872. Asplenium gracile (E. Fourn.) Hemsl., Biol. Cent.-Amer., Bot. 3: 634. 1885, hom. illeg., non Don, 1825, nec Fe´e, 1852, nec Pappe & Raws, 1858. Type. Mexico. [Distrito Federal:] “Vallis Mexicensis pr. Pedregal,” Bourgeau 252 (P!-3 sheets; isotypes MO!, NY!).
Asplenium glenniei Hook. & Baker, Syn. Fil., ed. 2, 488. 1874. Syntypes. Mexico. Glennie s.n. (K!), Bourgeau 252 (K!; isosyntypes P, US!; isosyntype and frag. NY!).
Unverified, Doubtful, or Mistaken Reports. Ags (Gonza´lez- Adame 70, HUAA, cited by Siqueiros-Delgado & Gonza´lez-Adame, 2004, but not verified). Hgo (reported by Mickel & Beitel, 1988, but not verified). Asplenium exiguum has small proliferous apical buds on the pinnae and sometimes pinnules, and also has subterminal rachis buds, but these are tiny and easily overlooked. The rachises may also become flagelliform and naked when humidity is sufficiently high (Mickel, 1976). No other Mexican spleenwort is so diversified in its means of vegetative reproduction. The report of this species from Nuevo Leo´n by Hinton and Hinton (1994), based on Hinton 20142, applies to A. ultimum. Asplenium exiguum was correctly reported from Nuevo Leo´n by Rodri´guez-Lo´pez and Arregui´n-Sa´nchez (1992), citing Sa´nchez s.n., herb. no. 18919, and Cedillo M. s.n., herb. no. 18931 (both UNL!).