Maesa from New Guinea: A New Species and a Revised Description of Maesa beamanii. Contributions to the Flora of Mt Jaya, X

Abstract

Summary. Maesa decipiens is described from montane forest in New Guinea. It is morphologically similar to Maesa beamanii, but differs in indumentum and leaf characters, as well ecological requirements. A revised description of M. beamanii is given, following recent field observations. Maesa Forssk. is an Old World genus of approximately 150 species of shrubs, small trees and scramblers. The genus was last monographed by Mez (1902), and the New Guinea members were revised by Sleumer (1987), who recognised 26 species. An additional four species have been described after recent field and herbarium observations (Utteridge 2000, 2001). During fieldwork in New Guinea in the PT-Freeport Indonesia (PT-FI) Contract of Work area in Papua (formerly Irian Jaya), in which several recently collected sites were revisited, a new species of Maesa was collected. This species is very similar in habit to M. beamanii Utteridge (Utteridge 2000), but was collected from a different habitat and altitude. In addition, there are several morphological differences from M. beamanii and the other species of Maesa in New Guinea, especially in leaf morphology and indumentum. The type and distribution of indumentum in Maesa is taxonomically very useful (Utteridge 1998). Indumentum terminology follows Hewson (1988); hair, for example, is defined narrowly as a special class of trichome, and indumentum is used as a term for the presence of trichomes. Two types of indumentum (sensu Hewson 1988), are found in the genus: single-celled hairs of variable length, and irregularly shaped peltate scales (see Caris et al. 2000: 89). Typically, most species of Maesa have peltate scales, especially on the young parts, but hairs may or may not be present; the new species described here has both scales and hairs.