Pecluma

• Authority

  Mickel, John T. & Beitel, Joseph M. 1988. Pteridophyte Flora of Oaxaca, Mexico. Mem. New York Bot. Gard. 46: 1-580.

• Family

  Polypodiaceae

• Scientific Name

  Pecluma

• Description

  Genus Description - Mostly epiphytic, less often epipetric or terrestrial; rhizome long- to short-creeping, unbranched, never glaucous, commonly proliferous by root buds; rhizome scales concolorous to bicolorous, non-clathrate, basally attached, surface glabrous or hairy (comose), margin entire or toothed; fronds pinnatifid with numerous linear segments, distant (less than 1.5 cm apart) or clumped, monomorphic, stipitate, narrowly elliptic to narrowly debate, base attenuate to truncate, articulate, phyllopodia 12 mm long; stipe black to reddish-brown, rarely light, terete (never channelled); blade curling in response to drought, sometimes with a few scales along the axes; rachis, costae and lamina with multicellular hairs; veins free, rarely casually anastomosing, usually with free included veins, simple or forking (in ours); sori round, exindusiate, terminal on first acropetal veinlet, in one row between costa and margin, paraphyses (simple or forked multicellular, clavate hairs) present; sporangia with simple, 1-3-celled paraphyses or glabrous; spores bilateral (globose in apogamous species, P. dispersa), verrucate to tuberculate.

• Discussion

  Type: Pecluma pectinata (Linnaeus) Price [=Polypodium pectinatum Linnaeus]. The species in Pecluma (as the “Polypodium pectinatum-plumula complex”) were revised by Evans (1968). Recognized as a strictly neotropical genus separate from Polypodium by Price (1983), the species in this complex have sometimes been included in the genus Grammitis (under Ctenopteris). They are a distinct group differing from Polypodium s.s. by Pecluma having short, non-branching rhizomes that are never glaucous, proliferous roots, non-clathrate rhizome scales that are basally attached, terete axes and pectinate fronds, and differing from Grammitis by having bilateral, non-green spores, articulate fronds, two-rowed sporangial stalks, lacking dark maroon, acicular, broad-based hairs. A peculiar type of hair, called “ctenoid” hairs by Evans (1968) is found in several species (P. dispersa, P. ptilodon, P. boliviana). They consist of an arching axis of ca. four cells, each with a 1- 2-celled lateral branch, all arising from one side of the axis, producing a comb-like trichome. References: Evans, A. M. 1968 [1969]. Interspecific relationships in the Polypodium pectinatum-plumula complex. Ann. Missouri Bot. Gard. 55:193-293; Price, M. G. 1983. Pecluma, a new tropical American fern genus. Amer. Fem J. 73: 109-116.