Gametophytes of Four Tropical Fern Genera Reproducing Independently of Their Sporophytes in the Southern Appalachians

Abstract

Vegetative reproduction and dispersal by way of gemmae are known to occur in four types of fern gametophytes. Although they belong to basically tropical rain-forest genera, all four types have now been discovered growing natu rally in the vicinity of Highlands, North Carolina, as clones on shady, damp rocks. Their sporophytes were rare or absent. The gametophytes are now identified as Grammitis nimbata (Jenm.) Proctor, Grammitidaceae; Hymenophyllum tunbridg ense (L.) J.Sm., Hymenophyllaceae; Vittaria lineata (L.) J.Sm., Vittariaceae; and Trichomanes, probably representing several species, Hynmenophyllaceae. Identifi cation of the Grammitis was facilitated by the presence of some juvenile or dwarfed sporophytes; this constitutes the first report of this species, genus, and family for temperate North America. Growth and spread of fern gametophytes independently of, and distant from, the corresponding sporophytes is a novel phenomenon which should be investigated in other parts of the world.