A Taxonomic Revision Of The Genus Pentatrichia (Asteraceae)

ABSTRACT

A new 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.) Marxism. were subjected to both univariate and multivariate statistical methods. Both herbarium material and voucher specimens collected during fieldwork were examined. Morphological character data were analysed by Unweighted Pair-group Method Arithmetic Average (UPGMA) clustering algorithms as to obtain groupings as objectively as possible. Cluster analyses revealed the existence of three species in the genus namely P. alata, P. Pedrosa and P. rehmii. Pentatrichia avasmontana Merxm. is reduced to subspecific level under P. rehmii (Merxm.) Merxm.; P. rehmii subsp. avasmontana (Merxm.) Klaassen & Kwembeya comb.nov. Two ordination methods Principal Coordinate Analysis (PCO) and Principal Component Analysis (PCA) were employed and confirmed the results obtained from the cluster analyses. The results revealed that P. avasmontana does not warrant specific status as it came out nested within P. rehmii. Pentatrichia avasmontana is accordingly reduced to subspecific level under P. rehmii. Leaf characters and presence/absence of ray florets proved to be the most important characters in diagnosing species in the genus. Photographs of some of the morphological characters are provided. This revision includes a new key for the species, descriptions and distribution maps at the quarter degree level. v Field assessments of Namibian species facilitated comprehensive Red List assessments of the genus in Namibia. Two taxa emerged as “Least Concern” with P. rehmii subsp. rehmii falling in the “Vulnerable” (VUD1) category