Melpomene, a New Genus of Grammitidaceae (Pteridophyta)

Abstract

Melpomene, a new genus of Grammitidaceae, is described, and combinations are made for the species known to belong to it. Melpomene can be distinguished from all other Grammitidaceae by its rhizome scales that are clathrate, basally cordate, and entire except at the apex where provided with one to ten minute papillae. The genus contains about 20 species and is primarily neotropical. This paper is one in a series that have set forth new generic concepts in neotropical Grammitidaceae. In the series, Grammitis sensu lato has been divided into smaller monophyletic groups that have not previously been known or recognized. These groups, given generic status, are Cochlidium (Bishop, 1978), Ceradenia (Bishop, 1988), Enterosora (Bishop & Smith, 1992), Grammitis (Bishop, 1977), Lellingeria (Smith et al., 1991), and Zygophlebia (Bishop, 1989). Each group is believed to be monophyletic because it is defined by several correlating characteristics. In this paper, we describe another monophyletic group within the Grammitidaceae: Melpomene (the name of the Muse of Tragedy). The distinctness of Melpomene was first recognized by the late L. Earl Bishop. We have determined what species belong to the genus and have found additional characteristics that define it. Therefore, we take sole reponsibility for the description of the genus and new combinations. Melpomene A. R. Smith & R. C. Moran, gen. nov. TYPE: Polypodium moniliforme Lagasca ex Sw., Syn. Fil. 33. 1806. = Melpomene moniliformis (Lagasca ex Sw.) A. R. Smith & R. C. Moran. Figure 1. Plantae epiphyticae terrestres vel rupestres; squamae rhizomatis clathratae denigratae brunneolae vel vulgo rubellae integrae, base cordatae, apice glandulis praeditae; phyllopodia absentia; folia plerumque pinnatisecta, hydathodis adaxialiter ornata; petioli et rhachides setosi, setis castaneis; venae non furcatae librae; sori rotundi superficiales. Epiphytic, epipetric, or terrestrial; rhizome erect or shortto long-creeping, the scales strongly clathNOVON 2: 426-432. 1992. rate, cordate basally and attached at a single point, usually blackish or reddish, never setulose, with one to several papillose cells (glandular?) ca. 0.1 mm long at the apex, these often dislodged and not p esent; phyllopodia absent; leaves pinnatifid, pinnatisect, or rarely 1-pinnate basally, linear to elliptic, pubescent and often setose, the hairs 0.1-0.2 mm long, branched, 2-8-celled, lax, pale reddish, with most of the color concentrated at the cross walls, the setae 0.3-3 mm long, castaneous, multicellular (the cross walls sometimes difficult to observe), erect to spreading; hydathodes present; veins free, often not visible; sori round or (rarely) slightly oblong, discrete, superficial or rarely slightly sunken, lacking globose, waxlike paraphyses, but some species with castaneous receptacular setae. In his revision of American grammitids (as Ctenopteris), Copeland (1955) treated the species of Melpomene in four of his ten species groups. He placed most of the species of Melpomene, however, under the group of C. moniliformis (Lagasca ex Sw.) J. Smith (the first of his ten groups). In this group he also included several species now placed in Lellingeria and a few species belonging to other genera. Copeland defined the C. moniliformis group very loosely, saying that it consisted of small, linear, coriaceous ferns that were related to Ctenopteris moniliformis (= Melpomene moniliformis). Obviously, Copeland's characterization of the group is not sufficient to establish monophyly. Yet Melpomene does appear to be monophyletic, and we have found several characteristics of the stem scales