Megalastrum gompholepis R.C.Moran & J.Prado
Descripción
Megalastro subinciso rhachidibus pinnarum abaxialiter glabris et divisionibus laminarum similis, sed ab eo rhachidibus et costis abaxialiter squamis atrofuscis patentibus basibus abrupte dilatatis indutis differt.
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 c. 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 × c. 0.5 mm long, the base usually expanded to slightly bullate, the apices filiform, patent, dark brown, shiny, denticulate, the hairs c. 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 c. 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.
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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 c. 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 × c. 0.5 mm long, the base usually expanded to slightly bullate, the apices filiform, patent, dark brown, shiny, denticulate, the hairs c. 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 c. 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.
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Ejemplar revisado
Chiapas: Motozintla de Mendoza, 45–50 km NE of Huixtla along rd to Motozintla, [15°22 ′N, 92°13 ′W], 1900 m, 17 Nov. 1971, Breedlove & Smith 22633 (F, MICH, MO, NY); Siltepec, ridge above Siltepec on the rd to Huixtla, [15°33 ′N, 92°19 ′W], 2000–2400 m, 18 Jan. 1973, Breedlove & Smith 31884 (F, NY); Unión Juárez, Volcán Tacaná por el camino de Talquián, por la linea divisoria con Guatemala, [15°40 ′N, 92°04 ′W], 2200-2400 m, 6 Feb. 1987, Martínez-S et al. 19692 (NY); Cerro del Boqueron, [15°10 ′N, 92°16 ′W], Aug. 1913, Purpus 6768 (NY).A
Elevación
1900 – 2400 mA
Tipo de vegetación
Bosque de neblina/mesófiloA
Categoría IUCN
No incluidaB
Categoría NOM-059-SEMARNAT-2010
No incluidaC
Discusión taxonómica
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, and slightly bullate at base. Also distinctive are the nearly hairless rachises, costae, and costules abaxially; in contrast, most species of Megalastrum are pubescent on the abaxial surfaces of these axes.
Specimens of Megalastrum gompholepis have previously been identified as 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 Mexico, Honduras, the Antilles, and northern Venezuela and Colombia (Moran et al. 2009b). M. 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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Specimens of Megalastrum gompholepis have previously been identified as 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 Mexico, Honduras, the Antilles, and northern Venezuela and Colombia (Moran et al. 2009b). M. 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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