Megalastrum grande (C.Presl) A.R.Sm. & R.C.Moran

  • Family

    Dryopteridaceae (Pteridophyta)

  • Scientific Name

    Megalastrum grande (C.Presl) A.R.Sm. & R.C.Moran

  • Primary Citation

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

  • Basionym

    Polypodium grande C.Presl

  • Description

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

    Type: Brazil. Rio de Janeiro: collector unknown, Christensen (1920) suspected J. E. Pohl s.n. (holotype: PR-n.v.; isotype: W?-n.v.).

    Description: Leaves to 1.0-1.5 m long; scales of the petiole bases ca. 1.5 × 0.05-0.07 cm long, linear, sparsely denticulate, brown, slightly twisted, en masse forming a woolly tuft; laminae 1 m long, to 2-pinnate at base (rarely 1-pinnate-pinnatisect), 1-pinnate-pinnatifid medially; basal pinnae 20-40 cm long, stalks to 1 cm long, inequilateral, pinnules acroscopically not or only slightly reduced toward pinna bases; pinna rachises abaxially non-glandular, glabrous to puberulent, sparsely scaly, hairs 0.1-0.2 mm long, 1-3-celled, scales 1-2 mm long, narrowly lanceolate, brown, denticulate, flat (non-bullate), adaxially non-glandular, glabrous; costules abaxially non-glandular, glabrous to puberulent, hairs 0.1-0.2 mm long, 1-3-celled, scaly, scales ca. 1 mm long, linear to narrowly lanceolate, non-bullate, sparsely denticulate, adaxially glabrous; laminar tissue between veins abaxially non-glandular, glabrous to subglabrous, hairs (when present) ca. 0.2 mm long, 1- or 2-celled, uniseriate scales often present, these appressed, reddish, inconspicuous, adaxially non-glandular, glabrous to sparsely pubescent (often near margins), hairs 0.3-0.4 mm long, 2- or 3-celled; veins visible or obscure on both surfaces, non-glandular, glabrous to sparsely pubescent (similar to lamina tissue between veins); lamina margins sparsely to densely ciliate, hairs 0.2-0.4 mm long, 1-3-celled; indusia absent.

    Distribution: Brazil, primarily Atlantic rainforest from Bahia to São Paulo; 300-1000 m.

    Comments: Megalastrum grande is unique in the genus by having the pinna rachises glabrous adaxially. It the least divided species in coastal Brazil, with laminae to 2-pinnate at the base, and usually broadly adnate segments that are slightly falcate. The hairs (when present abaxially) are generally inconspicuous, and the costal scales are sparse and linear to linear-lanceolate. Glandular hairs are absent from all parts of the plant. Although Christensen (1920) included Phegopteris scrobiculata as a synonym of Megalastrum connexum, the type at K and MO seem to us to be typical M. grande.

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