Adiantum braunii Mett.

  • Authority

    Mickel, John T. & Smith, Alan R. 2004. The pteridophytes of Mexico. Mem. New York Bot. Gard. 88: 1-1054.

  • Family

    Pteridaceae

  • Scientific Name

    Adiantum braunii Mett.

  • Description

    Species Description - Rhizomes short-creeping, 4–6 mm diam.; rhizome scales dark castaneous at rhizome apices to mostly black back from the tips, lustrous, 1.5–3 x 0.5 mm, margins entire; fronds 25–80 cm long, clumped, arching; stipes atropurpureous to blackish, lustrous, 20–40 cm x 1–2.5 mm, 1/2–2/3 the frond length, glabrous except for few broad scales at bases; blades broadly ovate, 3–4-pinnate proximally; rachises atropurpureous, glabrous; pinnae 5–8 compound pairs, alternate, stalked to 4 cm, axes with a pale spot at each branching point along rachises; pinnulets rhombicflabellate, orbicular, or obovate, mostly broadly cuneate (120– 180º, rarely less than 90º) at bases, 8–12 mm long, margins incised-lobate, stalked 1–10 mm, stalk color passing into pinnulet bases, non-articulate; veins free, forking, ending at the entire, cartilaginous margins or ending in very small teeth; indument absent on both sides of blades, blades not glaucous; idioblasts absent; sori 1–4 per pinnulet, confined to distal margins; indusia 1–8 mm long, linear-oblong to lunate, glabrous; 2n = 60 (Jal).

  • Discussion

    Type.Mexico. In 1830, Karwinski s.n. (B!; isotypes BR!, P! photo ex BR, US! photo ex BR). Adiantum braunii Mett. ex Kuhn var. cuneatum Mett. ex Kuhn, Linnaea 36: 75. 1869 [“cuneata”]. Type. Mexico. Berlandier 1151 (B, not seen). Adiantum convolutum E. Fourn., Mexic. Pl. 1: 127, t. 6. 1872. Syntypes. Mexico. Veracruz: Orizaba, Mpio. Orizaba, environs d’Orizaba, Botteri & Sumichrast 18 (P!-2 sheets; isosyntype BR!); Ghiesbreght 406 (P!-2 sheets; isosyntype US!). Unverified, Doubtful, or Mistaken Reports. Ags (Garci´a s.n., HUAA, cited by Siqueiros-Delgado & Gonza´lez-Adame, 2004, but not verified). This is a very common species on the western slopes of the Sierra Madre Occidental, at moderately low to middle elevations, but uncommon or absent elsewhere in Mexico. Among the 2–5-pinnate species with tapering blade apices, this species is distinguished by having non-articulate stalks with the color passing onto the pinnulet bases, and raised whitish patches at the bases of the costae. The specimen cited from Hidalgo is atypical in the small fronds and pinnulets and the lack of whitish patches at the bases of the pinnae.

  • Distribution

    Terrestrial in oak and pine woods, montane forests, deciduous forests, subtropical forests, tropical deciduous forests, and on lava flows; (150-)350-2200 m. Mexico; Guat, Salv, Nic, CR; Col, Ven, Ec.

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