1. Pecluma M. G. Price, Amer. Fern J. 73: 109. 1983.
[Latin pectinatus, in the form of a comb, and plumula, feathery, for the leaf blades]
A. Murray Evans
Polypodium Linnaeus subg. Pectinatum Lellinger
Plants terrestrial, on rock, or epiphytic. Stems short-creeping, unbranched, 4--8 mm diam., not whitish pruinose; scales concolored, ovate to linear-lanceolate, not clathrate, glabrous or pubescent, margins entire. Leaves monomorphic, crowded, narrowed toward tip, to 90 cm. Petiole dark brown to black, round in cross section except for narrow lateral ridge decurrent from base of blade. Blade narrowly oblong to linear, usually pectinate, with more than (20--)25 pairs of segments, not glaucous, pubescent, scales absent or on midrib only; rachis scaly and/or pubescent or glabrous abaxially, pubescent adaxially, scales basally attached and linear to cordate. Segments usually linear, 1.5--5(--8) mm wide, adnate to costa, closely spaced, margins entire, apex acute. Veins 1--2-forked [simple], occasionally anastomosing. Sori terminal on veins, round; indument of branched glandular hairs. Spores tuberculate. x = 37.
Species ca. 30 (3 in the flora): North America, Mexico, West Indies, Central America, South America.
Within Polypodiaceae, Pecluma is distinctive in its short-creeping stems, pectinate blades (usually with more than 30 pairs of segments), and ungrooved, adaxially pubescent rachises.
Many species of Pecluma are well adapted to dry seasons. As the leaves dry out, the segments curl inwardly, presumably retarding moisture loss. After rains, the segments uncurl, apparently undamaged by the period of dryness.
SELECTED REFERENCES
Evans, A. M. 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. Fern J. 73: 109--116.
