A New Species of the Fern Genus Thelypteris (Thelypteridaceae) from Southeastern Brazil

Abstract

Thelypteris semirii, known only from Minas Gerais, Brazil, is described and illustrated. The new species belongs to Thelypteris subg. Goniopteris, due to the indument of furcate and stellate trichomes on scales, petioles, rachises, and costae. It is most closely related to T scabra (C. Presl) Lellinger (from Argentina, Paraguay, and southeastern Brazil) because of pinna shape, disposition of indument, prominent sinuses, and unbranched trichomes on sporangial stalks. It differs by having trichomes golden or orange, stipitate, and glandular, on both surfaces of all pinnae and indusia. Stems are erect and buds are lacking in the axils of distal pinnae. Besides an early monograph by Christensen (1913) and the surveys of Brade (1972) and Sehnem (1979), nothing more on the taxonomy of the Brazilian species of the Thelypteris subg. Goniopteris (C. Presl) Duek has been published. This subgenus comprises 80 to 100 Neotropical species from Florida, the Antilles, and southern Mexico to northern Argentina and Paraguay (Smith, 1992). Thelypteris subg. Goniopteris is distinguished from other subgenera of Thelypteris by the presence of furcate or stellate trichomes on various plant parts, especially on the scales at the stem apex and in the adaxial groove of the rachis (Smith, 1983). Such trichomes are apparently lacking in a few species of subgenus Goniopteris (Smith, 1983, 1992), but are always present in Brazilian species. The major center of diversity for subgenus Goniopteris is Central America, where 41 species occur. Secondary centers are southeastern Brazil, Peru, and Ecuador. Brazil has approximately 29 species of subgenus Goniopteris, 21 of them occurring in the southeastern part of this country with at least 13 endemic to this region. In southeastern Brazil subgenus Goniopteris grows in mesic and moist shaded habitats, such as primary and secondary lowland and montane rainforests, from 0 to 1000 m, rarely reaching 1600 m. An exception is Thelypteris lugubris (Kunze ex Mettenius) R. Tryon & A. Tryon, which sometimes grows in open woods, along paths and weedy si s such as the understory of banana plantations. The present work provides the description of a new species and a key to the species of Thelypteris subg. Goniopteris of southeastern Brazil most closely related to this new species. Thelypteris semirii Salino & Melo, sp. nov. TYPE: Brazil. Minas Gerais: Marli(ria, Parque Estadual do Rio Doce, Campolina, Dec. 1996, Salino 2848 (holotype, BHCB; isotypes, UC, UEC). Figure 1A-E. Species nova subgeneris Goniopteridis, Thelypteridi scabra (C. Presl) Lellinger affinis, a qua pinnis trichomatibus glandulosis stipitatis abaxialiter vestitis et caule longo erecto differt. Stems erect, with caudex to 15 cm long, scales lanceolate, brownish, with furcate and stellate trichomes, sometimes also with marginal glandular trichomes. Leaves clustered, 64-103 cm long, monomorphic. Petioles yellowish, sulcate on adaxial side, 30-55 x 0.2-0.3 cm, glabrescent to sparsely pilose, with furcate and stellate trichomes up to 1.5 mm long, also with lanceolate scales. Laminae 34-59 cm long, herbaceous to chartaceous, not verrucose, 1-pinnate to pinnatifid, apex gradually reduced, confluent and pinnatifid. Buds and aerophores absent. Rachises densely pilose in adaxial grooves, abaxially sparsely pilose with furcate and stellate trichomes, sometimes also with unbranched trichomes, abaxially sometimes stellate and furcate trichomes absent. Pinnae 11 to 20 pairs per leaf, sessile, 9-12 x 1.3-2 cm, linear-lanceola e, elliptic or lanceolate, with apex acuminate and base truncate or oblique; incised ca. 1/2 their width, with lowermost pinnae strongly deflexed, hair-like scales on abaxial side of costae. Segments 3-6 mm w de, falcate, with margins entire and apex round* Author to whom correspondence should be addressed; salino@mono.icb.ufmg.br NovoN 10: 74-77. 2000. This content downloaded from 157.55.39.121 on Mon, 28 Nov 2016 04:04:15 UTC All use subject to http://about.jstor.org/terms