Elaphoglossum nigrescens (Hook.) T.Moore ex Diels

  • Family

    Dryopteridaceae (Pteridophyta)

  • Scientific Name

    Elaphoglossum nigrescens (Hook.) T.Moore ex Diels

  • Primary Citation

    Nat. Pflanzenfam. 1: 332. 1899

  • Description

    by: A. Vasco, R.C. Moran, and G. Rouhan

    Type: Venezuela (as "British Guiana"). Bolivar: Roraima, 1842, R. Schomburgk s.n. (holotype: K)

    Description: Epiphytic or rarely terrestrial. Rhizome 1-3 mm wide, compact, glabrous, black, resinous. Sterile leaves 11-30 cm long, 1-2 mm apart; phyllopodia present, 0.6-1 cm long; petioles 1/30-1/5 the length of the sterile lamina, stramineous to tan or light brown; scales absent or reduced to resinous dots; laminae 10-30 x 1.2-2 cm, narrowly elliptic or narrowly oblanceolate, papyraceous to chartaceous, the base decurrent all the way to the phyllopodia, the apex obtuse or broadly acute; veins conspicuous or inconspicuous, 1.5-2 mm apart, at a angle of 65° with respect to the costa, the apices free; hydathodes absent; lamina scales reduced to resinous dots, these often on both surfaces but more pronounced on the abaxial side; marginal scales sparse, 0.3-1 mm long, lanceolate to ovate, dissected. Fertile leaves longer than the sterile; petioles 2/3-3/4 the length of the fertile leaf, stramineous to black; laminae 3-5 cm wide, linear to narrowly elliptic, sometimes scaly, the base cuneate, the apex obtuse to broadly acute.

    Distribution: Nicaragua, Costa Rica, Panama, Colombia, Venezuela, Guyana, Ecuador, Peru, Brazil, Bolivia; elevation 60-1800 (-2000) m . This is the only species in the ciliatum-group that occurs in lowland Amazonia.

    Comments: Elaphoglossum nigrescens is distinguished by laminae that taper to the phyllopodia and dissected scales along the lamina margin. It varies with respect to the length of the fertile leaves; from shorter to much longer than the sterile. The specimens from southern Venezuela and the Guianas (where the type was collected) tend to have longer fertile leaves, whereas those from Costa Rica and Panama tend to have a higher occurrence of shorter ones. Plants from southeastern Brazil have mostly longer fertile leaves and non-black fertile petioles.

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