Polystichum platyphyllum (Willd.) C.Presl

  • Authority

    Mickel, John T. & Beitel, Joseph M. 1988. Pteridophyte Flora of Oaxaca, Mexico. Mem. New York Bot. Gard. 46: 1-580.

  • Family

    Dryopteridaceae

  • Scientific Name

    Polystichum platyphyllum (Willd.) C.Presl

  • Description

    Species Description - Rhizome suberect to erect; rhizome scales tan to brown, concolorous, broadly ovate, larger ones 5-10 mm long, 1-3 mm wide, mixed with thin, hairlike scales, 2-4 mm long, 0.5-0.8 mm wide, margins with long, twisted cilia; fronds clumped; stipe 25-50 cm long, ca. ½ the frond length, stramineous, with stipe base scales similar to those of rhizome, with sparse hairlike scales distally; blade 35-60(-70) cm long, 20-30 cm wide, lanceolate-attenuate, apex rather elongate and with simple pinnae similar to pinnules of lower pinnae; rachis with dense to scattered, twisted, hairlike scales, 1-7 mm long, nearly always with a small scaly bud in axil of a distal pinna; proximal pinnae pinnate to pinnate-pinnatifid, 10-15 cm long, 3-4.5 cm wide; pinnules oblong-rhomboid, 12-18 mm long, crenate along acroscopic margin, often with a single acroscopic auricle, entire along basiscopic margin, rounded, blunt, or aristate at tip; lower laminar surface glabrous, costae with scattered, hairlike scales; upper laminar surface glabrous except with scattered hairlike scales in costular groove and at base of pinnule; sori exindusiate.

  • Discussion

    Aspidium platyphyllum Willdenow, Sp. pl. 5: 255. 1810. Nephrodium platyphyllum (Willdenow) Desvaux, Mém. Soc. Linn. Paris 6: 261. 1827. Phegopteris platyphylla (Willdenow) Mettenius, Abh. Sencken-berg. Naturf. Ges. 2: 296. 1858. Polypodium platyphyllum (Willdenow) Hooker, Sp. fil. 4: 248. 1862, nom. illeg., non Swartz, 1806. Type. Venezuela. Caracas, Bredemeyer s.n. (B-Willd. 19789!). This exindusiate taxon bears a small bud in the axil of a distal pinna, which distinguishes it from all other Oaxacan Polystichums.

  • Distribution

    Terrestrial in wet montane forests; Cuicatlán, Juchitán, Juquila, Putla (200-)900-1450 m. Mexico (Ver, Oax, Chis); Hond, CR; Jam; Col & Ven to Bol, Braz & nw Arg.

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