A taxonomic revision of the genus Pentatrichia (Asteraceae)

A taxonomic revision of the genus Pentatrichia Klatt is presented here. Morphological data from previously described taxa: P. alata S.Moore, P. avasmontana Merxm., P. petrosa Klatt and P rehmii (Merxm.) Merxm. were subjected to both univariate and multivariate statistical methods. Herbarium material and specimens collected during fieldwork were examined. Morphological character data were analysed using Unweighted Pair-group Method Arithmetic Average (UPGMA) algorithm so as to obtain groupings as objectively as possible. Cluster analyses revealed the existence of three groupings in the genus that corresponded to P alata, P. petrosa and P. rehmii. Two ordination methods, i.e. Principal Coordinate Analysis (PCO) and Principal Component Analysis (PCA) were employed and confirmed the results obtained from cluster analyses. Pentatrichia avasmontana Merxm. is here reduced to subspecific level under P rehmii (Merxm.) Merxm.; P rehmii subsp. avasmontana (Merxm.) Klaassen & Kwembeya comb.nov. Leaf characters and presence/absence of ray florets proved to be the most important characters in diagnosing species in the genus. Field assessments of Namibian species facilitated comprehensive Red List assessments of the genus in Namibia. Two taxa, P rehmii subsp. avasmontana and P petrosa, emerged as "Least Concern" with P rehmii subsp. rehmii falling in the "Vulnerable" (VUDI) category. A new key for the species, descriptions and distribution maps at the quarter degree level are provided. (C) 2008 SAAB. Published by Elsevier B.V. All rights reserved.