Polystichum platyphyllum (Willd.) C.Presl

  • Authority

    Proctor, George R. 1989. Ferns of Puerto Rico and the Virgin Islands. Mem. New York Bot. Gard. 53: 1-389.

  • Family

    Dryopteridaceae

  • Scientific Name

    Polystichum platyphyllum (Willd.) C.Presl

  • Description

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    Species Description - Rhizome ascending to erect, 10-12 mm thick (excluding closely adhering stipe bases), densely clothed at apex with thin, brown or reddishbrown, ovate-oblong scales up to 10 mm long. Fronds spreading, mostly 70-115 cm long; stipes shorter than the blades, persistently scaly toward base, the scales like those of rhizome. Blades narrowly to broadly deltate-lanceolate or ovate, 40-70 cm long, 25-30 cm broad, 2-pinnate except toward the attenuate apex; rhachis stout (1.5-2.5 mm diam.), flexuous, deeply grooved adaxially, persistently fibrillose-scaly, and bearing a small scaly proliferous bud in a pinna-axil usually 7-10 cm from tip of blade. Larger pinnae lanceolate or narrowly oblong, 14-20 cm long, 3.5-4 cm broad, acuminate and somewhat falcate; pinnules obliquely ovate-oblong or rhombic-oblong, mostly short-stalked, strongly inequilateral, aristate at apex, the acroscopic margin spinulose-lobed with the basal lobe larger than the rest or subauriculate; veins 1- to 4-forked, naked or with a very few fibrillae abaxially; tissue firmly herbaceous, subtranslucent. Sori inframedial, uniseriate or with extra rows in basal lobes of pinnules; indusium absent.

  • Discussion

    Basionym. Aspidium platyphyllum Willdenow in Linnaeus, Sp. pL 5: 255. 1810.

    Type. Bredemeyer, from Caracas, Venezuela (Herb. Willd. 19789, B).

    Syn. Nephrodium platyphyllum (Willdenow) Desvaux, Mem. Soc. Linn. Paris 6: 261. 1827.

    Phegopteris platyphylla (Willdenow) Mettenius, Abh. Senckenberg. Naturf. Ges. 2: 296. 1858.

    Polypodium platyphyllum (Willdenow) Hooker, Sp. fil. 4: 248. 1862, not Swartz, 1806.

    Aspidium aculeatum (var.) ^ platyphyllum (Willdenow) Grisebach, Fl. Brit. W.L 689. 1864.

    Aspidium aculeatum of Jenman, Bull. Bot. Dept. Jamaica n.s. 2: 269. 1895, in part, not Swartz, 1802.

    Jamaica, Puerto Rico, and South America; related forms in Central America may bridge the morphological gap between this and the preceding species. Cytological study may be needed in order to understand the relationships among these forms. Distribution in Puerto Rico. Known from but three collections. Jayuya: Barrio Veguitas, Rio Veguitas, along headwaters tributary just S W of Piedra Blanca, 24 Mar 1984, Proctor 40389 (SJ, US); Maricao: Barrio Indiera Fria, ravine beside base of El Salto de Curet (Rio Lajas), 22 Nov 1983, Proctor 39811 (SJ, US); Peiiuelas: Cerro Garrote, 28 Mar 1987, Proctor 43243 (SJ US). Habitat. In humus on moist shaded rock-ledges or rocky banks beside streams at middle to high elevations (450-1100 m), very rare. The general characters of this species suggest that it may be an autotetraploid derived from P. polystichiforme, but this hypothesis needs to be tested.

  • Distribution

    Puerto Rico South America| Jayuya Puerto Rico South America|