Taxon Details: Megalastrum caribaeum (Desv.) R.C.Moran, J.Prado & Labiak
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Family:

Dryopteridaceae (Pteridophyta)
Scientific Name:

Megalastrum caribaeum (Desv.) R.C.Moran, J.Prado & Labiak
Accepted Name:

This name is currently accepted.
Description:

by: R.C. Moran, J. Prado, and P.H. Labiak

Type: "Caribaeis Antill.," collector unknown s.n. (holotype: P; photo US ex P).

Description: Leaves up to 2.5 m long; scales of the petiole bases 1.5-2.0 × 0.1-0.2 cm, linear-lanceolate, entire to subentire, light brown; laminae 1-2 m long, 3-pinnate-pinnatisect at base, 2-pinnate-pinnatisect medially; basal pinnae ca. 0.4 m long, strongly inequilateral; pinnules short-stalked, 4-10 cm long; pinna rachises abaxially sparsely glandular, scaly, glabrous to pubescent, the glands ca. 0.1 mm long, globose, yellowish, sessile, the scales 3-4 mm long, linear-lanceolate, light brown, entire to subentire, non-bullate, the hairs 0.2-0.4 mm long, 3-5-celled, rachises adaxially sparsely glandular, densely pubescent, the hairs 1.5-2 mm long, 5-8-celled, the scales like those of the abaxial surface; costules on the abaxial surface glandular, pubescent and scaly, the glands ca. 0.1 mm long, spherical, yellowish, sessile, the hairs 0.1-0.2(-0.5) mm long, 1- or 2-(-5)celled, the scales 1-3 × 0.1-0.3 mm, like those abaxially but smaller, linear to linear-lanceolate, parallel sided, scarcely enlarged basally, the adaxial surface pubescent, the hairs of two sizes, larger ones 1-1.5 mm long, 5-7-celled, and shorter 0.3-0.4 mm long, 2-4-celled, spreading to substrigose; laminar tissue between veins abaxially sparsely glandular, glabrous to puberulent on both surfaces, the glands ca. 0.1 mm long, spherical, yellowish, sessile, the hairs (when present) ca. 0.1 mm long, 1- or 2-celled, acicular, erect; veins visible on both surfaces, abaxially sparsely glandular and pubescent, minutely scaly, the hairs 0.2-0.4 mm long, 2- or 3-celled, the scales ca. 0.3 mm long, uniseriate, appressed, reddish, adaxially non-glandular, sparsely pubescent, the hairs 0.3-0.5 mm long, 1-3-celled; laminar margins ciliate, the hairs ca. 0.2 mm long, 1- or 2-celled, ascending, appressed, glandular hairs absent; indusia absent; n=41 (Walker, 1985).

Distribution and ecology: Cuba, Jamaica, Haiti, Dominican Republic, Guadeloupe, Martinique, St. Lucia, St. Vincent, Grenada, Trinidad, n. Colombia; wet forests, 200-1800 m.

Comments: Megalastrum caribaeum is one of the most common species in the Antilles. It resembles M. martinicense in laminar cutting and the presence of glands on the costules abaxially, but it differs by wider, more lanceolate scales that are entire or nearly so (not linear and denticulate), and by shorter denser hairs on the costules abaxially. Some specimens are acicular-pubescent between the veins abaxially, a condition that can also occur in M. martinicense. For this reason the species appears twice in the key. The hairs on the laminar margins tend to be more ascending and appressed than in M. martinicense, and the pinnules tend to be more obtuse. Megalastrum subincisum resembles M. caribaeum but differs by slightly wider, more lanceolate scale that are distinctly denticulate and less pubescent costules that lack spherical sessile glands abaxially. It occurs consistently at high elevations (900-1700 m), whereas M. caribaeum has a broader elevation range (200-1800 m). Outside the West Indies, Megalastrum caribaeum occurs only in northern Colombia in the Sierra Nevada de Santa Marta (Smith 1047, NY).