Authority:

Proctor, George R. 1989. Ferns of Puerto Rico and the Virgin Islands. Mem. New York Bot. Gard. 53: 1-389.

Family:

Hymenophyllaceae

Description:

Species Description - Epiphytes of mostly delicate texture. Rhizomes more or less filiform, wide-creeping, flexuous; fronds scattered, ascending or pendent, always stipitate in Puerto Rican species. Blades glabrous or hairy (the hairs simple, forked, or variously stellate), 1-several times pinnatifid or pinnate; rhachis terete or (more often) winged, the wings and ultimate segments ofthe blade flat or undulate-crispate, entire or toothed. Sori wholly immersed in the frond tissue to partly or entirely free; spores with surface more or less papillate. Chromosomes: n = 11, 13, 18, 21, 22, 26, 27, 28, 36, 42, 56, 72.

Discussion:

Type Species. Hymenophyllum tunbrigense (Linnaeus) J. E. Smith, based on Trichomanes tunbrigense Linnaeus, originally described from England but n o w known to be of scattered but nearly cosmopolitan distribution.

A large genus of about 300 species, of wide-spread distribution. The generic is derived from the Greek hymen, membrane + phyllon, leaf, alluding to the fact that the leaves are usually only one cell thick.

Special Literature. Morton, C. Y. 1947. The American species of Hymenophyllum section Sphaerocionium. Contr. U.S, Natl, Herb. 29: 139-201. (Note: at the subgeneric level this taxon must be called Leptocionium.)