A Synopsis of Mitthyridium (Musci: Calymperaceae) in Malaysia and Adjacent Regions

Abstract

Review of recent and historical specimens of Mitthyridium (Musci: Calymperaceae) from Malaysia, and adjacent regions reveals 12 species. A key, synonymy, diagnostic features, illustrations, and differentiation from similar species are given for these 12 species, together with an index to all names cited. This article concludes our review of Malaysian Calymperaceae that includes up to now a treatment of the genus Calymperes (Reese & Mohamed 1985) and one of Syrrhopodon (Mohamed & Reese 1985). The philosophy of our approach to the study of this family of tropical mosses is discussed in our two earlier publications. Manuel (1981) summarized Mitthyridium for peninsular Malaya and Singapore, and listed six species: M. fasciculatum, M. flavum, M. manii, M. undulatum, M. undulatulum, and M. wallisii. Of these six taxa, we recognize here M. fasciculatum, M. flavum, M. undulatum, and M. wallisii, while we regard M. manii and M. undulatulum as syn- onyms of M. repens. In addition, we also recognize here the presence in Malaysia of M. crassum, M. constrictum, M. jungquilianum, M. luteum, M. sub- luteum, M. cardotii, and M. obtusifolium. The distribution of Mitthyridium is almost ex- clusively in the paleotropics, with only a single his- torical collection of one wide-ranging species re- corded from the western coast of South America (Chile). The genus, as it occurs in Oceania, was re- vised by Nowak (1980), who provided keys, de- scriptions, illustrations, and distribution maps in her extremely valuable treatment. In general, syn- onymy already cited by Nowak and accepted in our study is not repeated here. Mitthyridium, a very natural genus of mosses, seems to be a taxonomically difficult group to study in the sense that it is often difficult to place names, with confidence, on specimens. Surprisingly, in spite of this difficulty, relatively few species have been described for the genus, especially as compared with its sister genera, Calymperes and Syrrhopodon.