Adiantum decoratum Maxon & Weath.

  • 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 decoratum Maxon & Weath.

  • Description

    Species Description - Rhizomes short-creeping, nodose, 4–7 mm diam.; rhizome scales concolorous, dark brown, 3–4 x 0.3–0.5 mm, margins denticulate; fronds clumped, 50–90 cm long, arching; stipes atropurpureous, 25–50 cm x 3–5 mm diam., with dense filiformsubulate spreading scales, these persistent, giving the stipes a shaggy appearance; blades 2-pinnate (rarely 3-pinnate proximally), each with a conform terminal pinna; rachises atropurpureous, with dense spreading dark brown scales similar to those of stipes, scales entire or denticulate, especially toward their bases; pinnae 5–7 pairs, each pinna ending in a small lanceolate pinnule, distal pinnules on each pinna reduced to less than half the size of largest pinnules; pinnules oblong, truncate or rounded at tips, 10–20 x 4–7 mm, the sterile serrulate along distal and acroscopic margins, oblique to spreading, not or only slightly falcate, short-stalked, non-articulate; veins free, forking, ending in marginal serrations; indument absent on both sides of blades, often glaucous abaxially; idioblasts present and conspicuous on both blade surfaces; sori 4–9 per pinnule, along acroscopic and distal margins of pinnules; indusia 1–3 mm wide, oblong to linear, glabrous.

  • Discussion

    Type. Panama. Panama´: Ri´o Tapia, Standley 26216 (US!). Unverified, Doubtful, or Mistaken Reports. Ver (Ventura s.n., ENCB, cited by Palacios-Rios, 1992, but not found and likely misidentified). This differs from other bipinnate species with idioblasts and conform terminal pinnae by the dense and spreading hair-like scales on the stipes and rachises. Several of the collections from Chiapas have the proximal pinnae (to three pairs) fully bipinnate at the bases, with three pairs of pinnate pinnules on both acroscopic and basiscopic sides. Of Mexican species, A. decoratum appears most closely related to A. tetraphyllum.

  • Distribution

    Terrestrial in lowland rain forests and lower montane forests; 100-350 m. Mexico; Guat, Bel, Hond, CR, Pan; nw Col.

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