Trichomanes polypodioides and Its Allies

Abstract

The identity of neotropical specimens of Trichomanes is often puzzling because the species vary in frond size and dissection according to the humidity and light intensity under which they grow and because many of the species are wide ranging and have accumulated different names in different countries. Although there has never been a modern monograph of the genus as a whole, Wessels-Boer (1962) treated the species of subg. Didymoglossum (Desv.) C. Chr. and more recently Windisch (1993) published on the T. crispum group, which are among the most vexing species of subg. Achomanes K. Presl. Trichomanes polypodioides L. is a rather common, widespread, lowland and midelevation epiphyte. It is often found on tree fern trunks and has short, strongly alate stipes and narrowly lanceolate, merely pinnatifid laminae with entire to sinuous or crenate lobes, a frond form that is rather unusual in Trichomanes. This species and its allies form section Acarpacrium (Prantl) C. Chr. of subg. Achomanes and are characterized by having stellate (or sometimes bifid) hairs, rather than simple hairs, on the lamina margins and usually on the veins. Morton (1968, pp. 198-199) included ten names in this section, five of which appear to be valid species. The disposition of the other names is as follows: Trichomanes adscendens Kunze is probably a synonym of T. holopterum Kunze, T. attenuatum Hook. and T. ptilodes Bosch are synonyms of T. alatum Swartz, T. curranii Weath. is a synonym of T. superbum Bosch, and T fimbriatum Backh. is a synonym of T. trigonum Desv. In studying these species for the Flora of the Guianas, I found some specimens that had been misnamed and were actually a new species: Trichomanes caliginum Lellinger, sp. nov. Figs. 1-3 Rhizoma repens, 1-1.5(2) mm in diam. Frondes subdistantae monomorphicae; axibus venisque abaxialiter stellato-pilosis, maturitate saepe glabriusculis. Stipites (1.5)4-12(20) cm longa, 1-1.5(2) mm lata, late alata, alis aliquando decrescentibus, margine stellato-pilosis, radiis 2-4-cellularibus manifeste septatis. Rachides uniformiter late alatae, marginibus stellato-pilosis, radiis 1(2)-cellularibus. Laminae 6-21(27) cm longae, 3-8(14) cm latae, juventute oblongae bipinnatifidae, maturitate lanceatae bipinnato-pinnatifidae; pinnis (10)15-25(30) paribus supoppositis vel alternatis, juventute leviter lobatis, maturitate pinnatifidis, segmentibus distanter angusteque serrato-lobatis, marginibus stellato-pilosis, radiis 1(2)-cellularibus. Involucra immersa, 1-1.5 mm longa, ca. 0.75 mm lata, juventute brevicylindrica truncata, maturitate eroso-subconica, protuberationibus lateralibus ulterius apicibus involucrorum extensis.