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Additional Resources:

Family:

Dryopteridaceae (Pteridophyta)

Primary Citation:

Amer. Fern J. 77(4): 127. 1987

Accepted Name:

This name is currently accepted.

Description:

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

Lectotype: (designated by Christensen, 1920): Brazil. Rio de Janiero: Rio de Janeiro, [22º56'S, 43º17'W], Glaziou 1781 (C; duplicates K, P, RB-n.v.; photos MICH, MO ex C).

Description: Leaves to 2.5 m long; scales of the petiole bases ca. 2 × ca. 0.1 cm, linear, sparsely denticulate, light brown, twisted, en masse forming a dense woolly tuft; laminae 1 m long, to 4-pinnate at base, 2-pinnate-pinnatifid medially; basal pinnae ca. 30-50 cm long, stalks to 2.5 cm long, strongly inequilateral, pinnules acroscopically slightly reduced toward the pinna bases; pinna rachises abaxially glandular, pubescent, hairs 0.8-1.2 mm long, 4- or 5-celled, densely glandular, glands ca. 0.1 mm long, 2-celled, scaly, scales ca. 1 mm long, lanceolate, subentire, flat (non-bullate), adaxially densely pubescent, hairs ca. 1 mm long, 3-6-celled, non-glandular; costules abaxially glandular, pubescent, hairs 0.3-0.4 mm long, 1-3-celled, glands ca. 0.1, 2-celled, scaly, scales ca. 1 mm long, bullate, subentire, adaxially pubescent, hairs 0.4-0.8 mm long, 1-3-celled, sparsely glandular, glands like those on the abaxial surfaces; laminar tissue between veins abaxially densely glandular and pubescent, hairs ca. 0.1 mm long, 1-celled, adaxially glandular but slightly less so than abaxially, hairs absent; veins visible on both surfaces, very sparsely glandular abaxially, pubescent abaxially, hairs 0.2-0.3 mm long, 1- or 2-celled, adaxially sparsely pubescent, hairs ca. 0.4-0.5 mm long, 1-3-celled; lamina margins densely ciliate, hairs ca. 0.3-0.4 mm long, 1- or 2-celled; indusia present, circular, dark brown, glandular, pubescent, or both, hairs 0.3-0.4 mm long, 1- or 2-celled.

Distribution: Venezuela, Brazil, and Paraguay; 725-1760 m.

Comments: Megalastrum crenulans is nearly unique in the region by having a large persistent indusium. It is further distinctive by glands on both surfaces of the laminae and bullate scales on the abaxial surfaces of the costules. The indusia are variable in the presence of hairs and glands, but no other character apparently correlates with this. The only other species with a well defined indusium is M. indusiatum, but the indusium in that species is much smaller, only about the size of a single sporangial capsule, and are easily overlooked. Fée (1869) applied the name Aspidium consobrium Fée, type from Guadeloupe, to the Brazilian specimens Glaziou 2350, 979, and Gaulthier s.n. In our opinion, these are typical M. crenulans. Aspidium consobrinum resembles M. subincisum and does not occur in Brazil.