Systematics of psilocaulon N.E.BR. (Aizoaceae)

On the basis of herbarium, living and pickled material the morphology and systematics of Psilocaulon N. E. Brown sensu Ihlenfeldt & Bittrich is investigated. Thirteen species (including one insufficiently known species) are recognized: P. articulatum, P. bicorne, P. coriarium, P. dimorphum, P. dinteri, P. foliosum, P. gessertianum, P. granulicaule, P. junceum, P. leptarthron, P. parviflorum, P. salicornioides, P. subnodosum. Species of Mesembryanthemum, Prenia, Brownanthus, Aspazom and Aptenia are used as outgroups in a cladistic analysis of Psilocaulon. The monophyly of Psilocaulon is demonstrated. As a result P. rapaceum Jacq. is excluded and transferred to Caulipsolon Klak gen. nov. The position of Psilocaulon and the monotypic genus Caulipsolon within the subfamily Mesembryanthemoideae is discussed. However, relationships of Psilocaulon and Caulipsolon to other genera remain obscure, since no synapomorphies were found to indicate sister relationships. More sampling among outgroups and/or a future molecular study may help to elucidate relationships among the genera of the Mesembryanthemoideae. Geographical distribution patterns for all species and the number of species per half-degree grid square are given. It is discussed how species diversity and geographical distribution in Psilocaulon contrasts with or corroborates existing ideas of centres of diversity and distribution patterns in the Mesembryanthema. Each species is described in detail. A description of the genera Psilocaulon and Caulipsolon is given and a key to the species is provided. Material examined is cited and full synonomy is given.

Grantor dc:publisher.institution

Department of Biological Sciences

Year dc:date.issued

1997

Author dc:creator

• Klak, Cornelia

Advisor dc:contributor.advisor

• Linder, H P

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/11427/17246

OAI identifier oai:identifier

oai:open.uct.ac.za:11427/17246