Blechnum polypodioides Raddi
Descripción
Rhizomes erect or ascending, stoloniferous; rhizome scales bicolorous, central portion or apices lustrous red-brown, outer or basal part pale brown, 3–5(–9) X 0.8–1 mm, lanceolate, margins entire; fronds 10–55 cm long, clumped; stipes stramineous, 2–10(–15) cm X 1–2 mm, 1⁄10–1⁄3 the frond length, smooth to papillate, at bases with scattered pale brown scales 2–3 mm long; blades thin-chartaceous, 14–30(–40) X (3–)4–6(–10) cm, pinnatisect, narrowly elliptic, proximal pinnae partially or completely adnate, often deflexed, distant and irregularly deltate, blade apices pinnatifid; rachises stramineous, with sparse scales 0.8–13 X 0.1–0.3 mm, otherwise either glabrous or with dense, sticky, septate hairs 0.3–0.5 mm long, lacking aerophores at pinna bases; pinnae 18–40 pairs, 1.5–3(–5) X 0.6–1 cm at bases, 3–4(–6) mm wide in middle, linear-oblong, straight to often falcate, adnate, surcurrent and auriculate, apices acute, often apiculate, margins entire, abaxially the costae glabrous or hairy with sparse to dense septate hairs 0.1–0.3 mm, adaxially glabrous, with an intramarginal row of minute teeth, costae grooved to ungrooved; veins simple or 1-forked, with slightly enlarged vein endings visible adaxially; indusia red-brown, 0.5 mm wide, entire to erose; 2n=124 (Jam, Trin, Galapagos).A
Forma de vida
or, rarely, epiphytic. TerrestreA
Ejemplar revisado
Chis (Breedlove 32486, DS, ENCB, MEXU, NY; Purpus 6740, MO, UC, US). Gro (Lorea 2840, FCME, IEB, NY). Jal (s. coll. 21287, NY). Méx (Sánchez 8, FCME). Nay (Breedlove 44308, CAS, MEXU; Téllez 9430, ENCB, MEXU). Oax (Mickel 1096, ENCB, MEXU, NY, 3989, MEXU, NY). Pue (Rzedowski 29976, ENCB). Sin (Mexia 424, B, CAS, UC, US). Ver (Copeland herb. 49, BM, MEXU, MICH, NY, UC, US).
A
A
Elevación
50 – 1450(– 3000) mA
Ecología y Hábitat
On open or lightly shaded banks at middle elevations.A
Tipo de vegetación
Bosque de pino-encinoA
Categoría IUCN
No incluidaB
Categoría NOM-059-SEMARNAT-2010
No incluidaC
Discusión taxonómica
Blechnum polypodioides is distinguished from other monomorphic taxa by its narrowly elliptic blades that gradually taper at both ends, pinnatifid blade apices, greatly reduced, adnate, proximal pinnae, and relatively thin-chartaceous blades; a few proximal pinna pairs are distant and irregularly deltate. Stipes are short, mostly 2–10(–15) cm long, about 1⁄3–1⁄10 the frond length. Blades are variably pubescent, totally glabrous on the Atlantic slope and usually with hairy rachises and sometimes also laminar surfaces abaxially on the Pacific slope. The nomenclature of this species, confused with Blechnum polypodioides (Sw.) Kuhn [a synonym of B. fragile (Liebm.) C.V. Morton & Lellinger], was clarified by Morton and Lellinger (1967). Blechnum polypodioides is part of the Blechnum occidentale complex, and hybrids are suspected with both B. appendiculatum and B. occidentale (which see for discussion).Walker (1966, 1973, 1985), in studies in Jamaica and Trinidad, found the species (as B. unilaterale) to be tetraploid and to hybridize with B. occidentale s.l., producing sterile tetraploids that formed large colonies by vegetative reproduction. Blechnum asplenioides Sw., a close relative in South America, has even narrower blades and lacks stipes altogether, or nearly so; pending further study, it appears sufficiently distinct to maintain at species rank.A