Vittaria

Abstract: Based on phylogenetic analysis of rbcL gene sequences from species of Vittariaceae, Vittaria and Antrophyum are, respectively, polyphyletic and paraphyletic. New circumscriptions are developed with the goal of organizing the species into genera that are strictly monophyletic. Species of Vittaria are placed in three genera, Vittaria, Haplopteris, and Radiovittaria, reflecting new hypotheses of their phylogenetic relation- ships. Species with leaves 4 mm wide and paraphyses bearing narrow apical cells are retained in Vittaria. Old World species with funnelform terminal cells on paraphyses and distichous phyllotaxy are placed in Haplopteris, whereas those with funnelform terminal cells on paraphyses and spiral phyllotaxy are placed in the new genus Radiovittaria. Species of Antrophyum are divided between the monophyletic genera Antrophyumn and Scoliosorus. Antrophyum is restricted to paleotropical species with pluriseriate venation and globose- tetrahedral spores. Those species with pluriseriate venation (neotropical and African) and bilateral spores are assigned to Scoliosorus. The genera Ananthacorus, Anetium, Hecistopteris, Monogramma, and Polytaenium are retained and given clarified circumscriptions. A description of the Vittariaceae and a key to the genera of the family are presented; all genera are described and new combinations are made for a number of species.

Abstract: The fern family Vittariaceae contains nearly 100 species of tropical epiphytes with simple leaf morphology. Different interpretations of the limited number of morphological char- acters has led to controversy in the generic and subgeneric taxonomy of the family. A 1380 bp fragment of the chloroplast-encoded rbcL gene was amplified and sequenced from species repre- senting the genera and subgenera of the family. Parsimony analysis of the sequence data resulted in two most parsimonious trees which differ only in the position of the monotypic Ananthacorus. Each tree has two main clades which separate in a basal dichotomy. In the first principal clade, Ananthacorus appears either as sister to a clade containing Antrophyum ensiforme and A. bor- yanum or sister to a clade containing Vittaria lineata, V graminifolia, V. dimorpha, and V isoeti- folia. The other principal clade is made up primarily of species divided into two sister groups. One of these groups contains only Old-World species of Vittaria while the other contains New- World species of Vittaria corresponding to Benedict's subgenus Radiovittaria with Hecistopteris sister to the latter clade. The rbcL topology is congruent with the character-state distributions for several morphological characters: Spore shape, paraphysis terminal cell shape, gametophyte gem- ma development, and leaf arrangement on the rhizome. The fern family Vittariaceae contains approximately 100 species of tropical epiphytes with distinctive morphology (Tryon and Tryon, 1982). The leaves are entire in all but one species, and the sporangia, without indusia, occur along veins. This distinctive but simple morphology makes the familial limits uncontroversial but provides few characters useful for intrafamilial taxonomy. Both the paucity of characters and disagreement about their interpretation has led to disagreement about generic circumscription. The number of genera rang- es from five to ten depending on which characters are considered significant (Benedict, 1911; Copeland, 1947; Tryon and Tryon, 1982). The genera of the Vittariaceae are defined by most authors using a combi- nation of venation and soriation (see Fig. 1). In Vittaria J.E. Smith, the veins enclose a single rank of areolae between the costa and the margin of the leaf, and a single line of sporangia follows the commisural marginal vein (Fig. lb, c). Antrophyum Kaulf. has several ranks of areolae, and several soral lines lying over the veins between the costa and the margin. A third genus, Mono- gramma Schkuhr, is composed of exceedingly small plants (laminae less than 1 mm wide) with either a single vein or a simple vein loop, and with the sporangia restricted to one margin (Fig. lg). Most species are included in these three genera; the three remaining genera, Ananthacorus Underw. & Maxon, Anetium Splitg., and Hecistopteris J. Smith, are monotypic. The largest genus, Vittaria, is a pantropical group of about 50 species. The leaves are lanceolate to long-linear, with venation consisting of a midrib and