Polytaenium chlorosporum (Mickel & Beitel) E.H.Crane
Descripción
Rhizomes erect to short-creeping; rhizome scales lanceolate, 3–4 mm long; fronds 12–20 X 1.3–2.2 cm wide, clumped; stipes absent; blades papyraceous, narrowly oblanceolate to almost elliptic, bases long-attenuate, decurrent, 2 mm wide, apices acuminate; veins netted, oblique, those near blade margins free, midribs prominent; sporangia (sori) following the entire vein pattern, surficial, not impressed in grooves; spores green.A
Forma de vida
EpífitaA
Ejemplar revisado
Chis (Breedlove 32212, DS, 35203, DS, MEXU, 38946, DS, NY, 49719, CAS). Oax (only the type collection).A
Elevación
1100 – 1800 mA
Tipo de vegetación
Bosque de neblina/mesófiloA
Categoría IUCN
No incluidaB
Categoría NOM-059-SEMARNAT-2010
No incluidaC
Discusión taxonómica
The green spores, thin blade texture, and free marginal veins distinguish this species from its Mexican congeners. It seems quite peculiar that P. chlorosporum, and no other species in the genus (or family, for that matter) produces chlorophyllous spores, but we have been unable to document this condition in any other neotropical Vittariaceae. Perhaps the green-spored state is a function of certain environmental conditions, but in the absence of an explanation we maintain the species as distinct, based not only on this spore character, but also the free veins that are oblique or nearly perpendicular to the blade margins.
Collections from Chiapas were previously cited by Smith (1981: 34) as Antrophyum guayanense Hieron., a species we now believe to be confined to Trinidad and South America (Col, Ven, Sur, Fr Gui, Peru, Braz, Bol). Polytaenium guayanense (Hieron.) Alston is perhaps a close ally of P. chlorosporum, but it lacks green spores; another close relative may be Polytaenium anetioides (Christ) Benedict, from Costa Rica, which lacks prominent blade midribs. Polytaenium cajenense differs from P. chlorosporum in having pale yellowish spores, sunken veins and sori, oblanceolate, coriaceous fronds, and marginal areoles.A
Collections from Chiapas were previously cited by Smith (1981: 34) as Antrophyum guayanense Hieron., a species we now believe to be confined to Trinidad and South America (Col, Ven, Sur, Fr Gui, Peru, Braz, Bol). Polytaenium guayanense (Hieron.) Alston is perhaps a close ally of P. chlorosporum, but it lacks green spores; another close relative may be Polytaenium anetioides (Christ) Benedict, from Costa Rica, which lacks prominent blade midribs. Polytaenium cajenense differs from P. chlorosporum in having pale yellowish spores, sunken veins and sori, oblanceolate, coriaceous fronds, and marginal areoles.A