Monograph of Trichanthecium, A New Genus Segregated from Panicum (Poaceae, Paniceae) Based on Morphological and Molecular Data

ZULOAGA, FERNANDO OMAR; MORRONE, OSVALDO; SCATAGLINI, M. AMALIA

Systematic Botany Monographs

The American Society of Plant Taxonomists

Año: 2010

0737-8211

Taxonomic features of species of Panicum, previously classified in section Parvifolia and Verruculosa, are reviewed and compared with those of other taxa in the Paniceae. The new genus Trichanthecium is proposed on the basis of shared morphological characters, including presence of membranous ligules, inflorescences lax and open, spikelets ellipsoid to obovoid, pilose or glabrous, lower glume nearly ½ to as long as the spikelet, (1-)3-nerved, upper glume 3-5 nerved, and upper anthecium indurate with globose or elongated bicellular microhairs and simple papillae all over its surface. This generic delimitation was confirmed with molecular phylogenetic studies, utilizing analyses chloroplast ndhF and rpoA sequences. As a result, a total of 38 American and African species are recognized within the genus Trichanthecium, and therefore a total of 38 new combinations are proposed. The new genus is compared  with other genera of the Paniceae. Lectotypes are designated for  Isachne trochainii A. Camus, Panicum carannasense Mez, P. cyanescens var. rigidiusculum Döll, Panicum frederici Rendle, P. fulgens Stapf, P. fulgens var. pubescens Robyns, P. gracilicaule Rendle, P. helobium Mez ex Henrard, P. ianthum Stapf, P. mueense Vanderyst, P. natalense Hochst., P. plagianthum Stapf, P. pubiglume Stapf, P. schwackeanum Mez, and P. sublaetum Stapf.