Megalastrum gompholepis R.C.Moran & J.Prado

  • Family

    Dryopteridaceae (Pteridophyta)

  • Scientific Name

    Megalastrum gompholepis R.C.Moran & J.Prado

  • Description

    by: R.C. Moran, J. Prado

    Type: Guatemala. San Marcos: near Aldea Fraternidad, between San Rafael Pie de la Cuesta and Palo Gordo, W facing slope of the Sierra Madre Mountains, [14°56'N, 91°49'W], 1800-2400 m, 10-18 Oct 1963, L. O. Williams et al. 25752 (Holotype: NY; Isotypes: F, GH, MO, US).

    Description: Leaves up to 2 m long; scales of the petiole base 10-30 × 0.1-0.3 mm, linear, brown, shiny, sparsely and minutely denticulate on the margins, the teeth often bifid; laminae 1-1.5 m long, up to 3-pinnate-pinnatisect at the base, 2-pinnate-pinnatisect medially; basal pinnae ca. 0.5 m long, strongly inequilateral (elongated basiscopically); pinna rachises abaxially non-glandular (lacking both stipitate or sessile glands), subglabrous, scaly, the scales 0.2-5 × ca. 0.5 mm long, the base usually expanded to slightly bullate, the apices filiform, patent, dark brown, shiny, denticulate, the hairs ca. 0.2-0.3 mm long, 1- or 2-celled, erect, acicular, adaxially densely pubescent, the hairs 0.4-1 mm long, 3-5-celled, erect to slightly strigose, acicular; costules on both surfaces with indumenta like that of the pinna rachises; laminar tissue between veins on both surfaces non-glandular, glabrous, proscales present, appressed, reddish; veins on both surfaces obscure, sparsely pubescent to glabrous, the hairs ca. 0.2 mm long, erect, acicular, adaxially sparsely pubescent to glabrous, hairs 0.5-0.7 mm long, 2- or 3-celled; hydathodes evident; lamina margins ciliate, the hairs 0.3-0.5 mm long, 2- or 3-celled, acicular, substrigose, non-glandular; indusia absent.

    Distribution: Southern Mexico, Guatemala; cloud forests, wet forests, montane rain forests, 1800-3000 m.

    Comments: The specific epithet is derived from the Greek, gompho-, nail, and lepis, scale. It refers to the scales on the rachises, costae, and costules abaxially that are often gomphoid, or nail-shaped. Such scales have an abruptly widened base resembling the head of the nail and an elongated apical portion resembling the shaft of the nail. These scales are typically patent, conspicuous to the eye, and slightly bullate at base. Also distinctive are the nearly hairless rachises, costae, and costules abaxially; most species of Megalastrum are pubescent on the abaxial surfaces of these axes. Megalastrum gompholepis has previously been called M. subincisum (Willd.) A. R. Sm. & R. C. Moran (Mickel & Smith, 2004; Stolze, 1981; Smith, 1981); however, we treat that species in a narrow sense (type from Caracas, Venezuela), occurring in the Antilles and northern Venezuela and Colombia (Moran et al., in press). Megalastrum subincisum also has axes glabrous abaxially, but its scales on these axes differ by being lanceolate, flat (never slightly bullate at base), light brown, and appressed to slightly spreading.

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