Vernonieae (Asteraceae) of southern Africa: A generic disposition of the species and a study of their pollen.

Harold Robinson,Vicki Funk,John Skvarla

doi:10.3897/phytokeys.60.6734

Abstract

Current and previously included members of the Tribe Vernonieae (Asteraceae) of southern Africa are listed in their presently recognized genera with complete synonymies and keys to genera and species. The genus Vernonia, as presently delimited, does not occur in Africa. Genera of the Vernonieae presently recognized from southern Africa are Baccharoides, Bothriocline, Cyanthillium, Distephanus, Erlangea, Ethulia, Gymnanthemum, Hilliardiella, Oocephala, Orbivestus, Parapolydora, Polydora, Vernonella, Vernoniastrum, plus two genera that are named as new: Namibithamnus and Pseudopegolettia. Twelve new combinations are provided and two species, Vernonia potamiphila and Vernonia collinii Klatt., hom. illeg., remain unplaced because of a lack of material.Pollen types are illustrated including previously recognized types: non-lophate, sublophate, tricolporate lophate, and non-colpate triporate lophate. A type previously unknown in the Asteraceae is described here and in a separate paper for Oocephala and Polydora; a non-colpate pantoporate lophate type with pores not strictly equatorial.

Highlights

Attempts to revise the generic concepts of the tribe Vernonieae (Asteraceae: subfamily Cichorioideae) in Africa have proven difficult, but it is possible to resolve most of the generic limits within the tribe in the more limited area of southern Africa here defined as including the following: Botswana, Lesotho, Namibia, Republic of South Africa, and Swaziland
This treatment is the latest in a series of papers revising the generic limits in the Vernonieae, a series that includes an initial summary of eastern hemisphere taxa (Robinson 1999a), a summary of western hemisphere taxa, (Robinson 1999b), the Vernonieae of China (Robinson and Skvarla 2010) and the Vernonieae of Thailand (Bunwong et al 2014)
As elsewhere in the series, changes are necessitated by the discovery of the natural limits of the genus Vernonia Schreb., typified by V. noveboracensis (L.) Michx., which is known to be almost entirely restricted to North America (Robinson 1999a, b) and is native only in the western hemisphere

Summary

Introduction

Attempts to revise the generic concepts of the tribe Vernonieae (Asteraceae: subfamily Cichorioideae) in Africa have proven difficult, but it is possible to resolve most of the generic limits within the tribe in the more limited area of southern Africa here defined as including the following: Botswana, Lesotho, Namibia, Republic of South Africa, and Swaziland. From the more basal subtribes (based on DNA studies by Keeley et al 2007), i.e. Distephaninae (Distephanus), Linziinae (Baccharoides, Linzia), and Gymnantheminae (Gymnanthemum), all have tricolporate pollen grains that are either lophate or sublophate. Subtribe Centrapalinae: Hilliardiella, Oocephala, Polydora, Parapolydora Subtribe Distephaninae: Distephanus Subtribe Erlangeinae: Bothriocline, Cyanthillium, Erlangea, Ethulia, Namibithamnus, Orbivestus, Pseudopegolettia, Vernoniastrum Subtribe Gymnantheminae: Gymnanthemum Subtribe Linziinae: Baccharoides, Linzia, Vernonella-placement uncertain Subtribe Unknown: Vernonia potamophila

Results

Conclusion