Taxonomic studies in the Miconieae (Melastomataceae). I. Variation in inflorescence position

Abstract

In the Miconieae (Melastomataceae) the inflorescences may be either lateral (with shoots pleonanthic and plants showing Rauh's architectural model) or the terminal (with shoots hapaxanthic and plants illustrating Leeuwenberg's, or less commonly Scarrone's or Stone's, architectural models). Inflorescence position is a valuable taxonomic character in the tribe and is usually uniform within genera or speciesgroups. An analysis of variation of this character elucidates the complex and difficult generic delimitations within the tribe.Ossaea DC. andClidemia D. Don, as presently delimited, contain both terminal-and axillary-flowered species and are undoubtedly polyphyletic assemblages. Some groups, e.g.,Clidemia sect.Clidemia, Leandra Raddi sect.Chaetodon Cogn.,Ossaea sect.Octopleura (Griseb.) Cogn., andMyrmidone Mart. have species that develop pseudolateral inflorescences, i.e., the terminal nature of the inflorescence is obscured by the early development of an axillary bud which continues growth of the branch. Pseudolateral inflorescences seem to have evolved several times within the tribe, andClidemia sect.Clidemia likely evolved from the obviously terminal-floweredHeterotrichum DC. andMiconia Ruíz & Pavón sect.Octomeris Hook. f. (p. p.);Myrmidone andMicrophysca Naud. are closely related toTococa Aublet; andLeandra sect.Chaetodon (and probably alsoOssea sect.Octopleura) show affinity with the remaining sections ofLeandra.