Megalastrum retrorsum R.C.Moran, J.Prado & Labiak

Creator(s): J. Garrison, R. C. Moran

Description: Specimen Voucher: Brade 12712 (NY) Scale bar = 10 micrometers. Spore photo by Judith Garrison Hanks and Robbin Moran.

Rights: Rights reside with creator, otherwise property of NYBG.

  • Family

    Dryopteridaceae (Pteridophyta)

  • Scientific Name

    Megalastrum retrorsum R.C.Moran, J.Prado & Labiak

  • Primary Citation

    Amer. Fern J. 99: 29, Figs. 4A, 6B, 8P–S. 2009

  • Type Specimens

    Specimen 1: Isotype -- A. C. Brade 12712

  • Description

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

    Type: Brazil. Rio de Janeiro: Itatiaia, Rio Bonito, [23º10'15"S, 44º50'08"W], 900 m, Sep 1933, Brade 12712 (holotype: NY; isotypes: MO, RB)

    Description: Leaves to 1.5 m long [estimate]; scales of the petiole bases ca. 1.5 × 0.2 cm, narrowly lanceolate, retrorsely denticulate, brown, flat (not twisted), en masse not forming a woolly tuft; laminae to 1 m long, to 3-pinnate-pinnatifid at base, 2-pinnate-pinnatifid medially, dull on both surfaces, paler abaxially; basal pinnae 30-40 cm long, stalks to 2 cm long, inequilateral, pinnules acroscopically slightly reduced toward the pinna bases; pinna rachises abaxially non-glandular, puberulous, scaly, hairs 0.1-0.2 mm long, 2- or 3-celled, patent, scales ca. 5 mm long, narrowly lanceolate, brown, retrorsely denticulate, flat (not bullate), adaxially non-glandular, puberulent, hairs ca. 0.4-0.7 mm long, 3-5-celled, patent; costules abaxially non-glandular, puberulent, hairs ca. 0.1-0.2 mm long, 1-3-celled, scaly, scales like those of pinna rachises but smaller, ca. 3 mm long, adaxially puberulent, hairs ca. 0.3-0.5 mm long, 3- or 4-celled; laminar tissue between veins abaxially non-glandular, densely to sparsely puberulent, hairs ca. 0.1, 1- or 2-celled, mixed with some inconspicuous, uniseriate, appressed, reddish scales, adaxially densely puberulent, hairs 0.2-0.3 mm long, 1-3-celled, erect; veins visible or obscure on both surfaces, non-glandular, abaxially densely puberulent and inconspicuously scaly, hairs ca. 0.1 mm long, 1- or 2-celled, adaxially densely puberulent, hairs ca. 0.3 mm, 1-3-celled; lamina margins sparsely puberulent, hairs ca. 0.1-0.2 mm long, 1- or 2-celled, substrigose; indusia absent.

    Distribution: Endemic to Rio de Janeiro, Brazil; wet forests, 900-1450 m.

    Comments: Megalastrum retrorsum is named for its retrorsely denticulate scales, a character it shares with M. organense. It can be distinguished from M. organense by the abaxial surfaces of laminae densely and evenly puberulent between the veins, whereas M. organense is glabrous between the veins.

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