Taxon Details: Megalastrum crenulans (Fée) A.R.Sm. & R.C.Moran
Taxon Profile:
Narratives:
Family:
Dryopteridaceae (Pteridophyta)
Dryopteridaceae (Pteridophyta)
Scientific Name:
Megalastrum crenulans (Fée) A.R.Sm. & R.C.Moran
Megalastrum crenulans (Fée) A.R.Sm. & R.C.Moran
Accepted Name:
This name is currently accepted.
This name is currently accepted.
Synonyms:
Aspidium crenulans Fée
Ctenitis crenulans (Fée) Ching
Dryopteris crenulans (Fée) C.Chr.
Dryopteris villosa var. glandulosa Rosenst.
Dryopteris crenulans f. glandulosa Rosenst.
Aspidium crenulans Fée
Ctenitis crenulans (Fée) Ching
Dryopteris crenulans (Fée) C.Chr.
Dryopteris villosa var. glandulosa Rosenst.
Dryopteris crenulans f. glandulosa Rosenst.
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.
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.
Related Objects:
• A. C. Brade 9695, Brazil
• J. Prado 2026, Brazil
• J. Prado 2026, Brazil
• J. Prado 2026, Brazil
• J. Prado 2026, Brazil
• J. Prado 2026, Brazil
• R. L. Liesner 21585, Venezuela
• R. L. Liesner 21585, Venezuela
• Collector unspecified s.n., Brazil
• Collector unspecified s.n., Brazil
• J. Miers s.n., Brazil
• Y. E. J. Mexia 5060, Brazil
• A. Salino 13899, Brazil
• A. Salino 5615, Brazil
• A. Salino 7078, Brazil
• J. Prado 2026, Brazil
• J. Prado 2026, Brazil
• J. Prado 2026, Brazil
• J. Prado 2026, Brazil
• J. Prado 2026, Brazil
• R. L. Liesner 21585, Venezuela
• R. L. Liesner 21585, Venezuela
• Collector unspecified s.n., Brazil
• Collector unspecified s.n., Brazil
• J. Miers s.n., Brazil
• Y. E. J. Mexia 5060, Brazil
• A. Salino 13899, Brazil
• A. Salino 5615, Brazil
• A. Salino 7078, Brazil