Plants epiphytic. Stems erect, slender, bearing clustered leaves and numerous, slender, wiry roots, clothed at apices with dark, multicellular, gland-tipped hairs. Leaves lanceolate-oblong, pinnatifid, 2.5--10 × 0.5--2 cm, with sparse, 2-celled glandular hairs on veins; petioles shorter than blades. Venation pinnate, without unconnected false veins. Soral involucres terminal on vein ends at pinna apices, broadly conic and flaring at mouth. Gametophytes composed of proximal filamentous network supporting aerial blades tipped by gemmae. Gemmae regularly 4-celled with 2 green body cells and 2 nongreen rhizoid primordia. 2n = 128. Epiphytic on decaying stumps and logs of bald cypress in dense cypress swamps; below 10 m; Fla.; West Indies. Although mature sporophytes of Trichomanes holopterum are very rare, gametophyte colonies are relatively common and more extensive and usually bear numerous young sporophytes, most of which seem unable to grow beyond a height of 1--2 cm. Persistence and vegetative reproduction by the gametophyte generation appear primarily responsible for maintenance of the species in the flora (C. E. Delchamps 1966; D. R. Farrar and W. H. Wagner Jr. 1968). The species probably also occurs elsewhere in cypress swamps along the Gulf Coast.