Cape Flora Research Interests: Oxalis biosystematics

The general systematics of the southern African members of Oxalis is poorly understood. The most recent revision is limited to a macro-morphological overview in which the infra-generic classification is questionable. Before any reliable phylogenetic picture for the genus can emerge, it is essential that systematically informative morphological characters are identified and studied. Work in this regard is currently underway, and will be expanded upon during the next few years. Constructing a robust species-level molecular phylogeny for the African members of Oxalis is another main priority of this research. Once in place, it will provide the framework for the study of character evolution and speciation in Oxalis. The state of expression of the tristyly syndrome among South African members of Oxalis is also being assessed by studying the morphology of reproductive structures, ancillary characters associated with tristyly, morph frequencies and self-incompatibility of selected taxa.

Other research interests:

Zygophyllum systematics

Hybridization in the Cape Flora

Interorganismal interaction in the Cape Flora

Palynology

Kariology

Recent Publications

Kumwenda, M.W. , Dreyer, L.L. & Marais, E.M. 2004. A taxonomic reassessment of the varieties of Oxalis minuta (Oxalidaceae) and the change of O. minuta var. callosa to specific rank as O. hygrophila. S. Afr. J. Bot. 70(2): 259-264.

Oberlander, K. C., Dreyer, L.L., Bellstedt, D.U & Reeves, G. 2004. Congruence of trnL-F and palynological data sets in the southern African Oxalis L. section Angustatae subsection Lineares. Taxon 53(4): 977-985.

Ressayre, A, Dreyer, L.L., Triki-Teurtroy, S., Forchioni, A., Nadot, S. 2005. Post-meiotic cytokinesis and pollen aperture pattern ontogeny: comparison of development in four species differing in aperture pattern. Am. J. Bot. (in press)

Nadot, S., Penet, L., Dreyer, L.L. & Ressayre, A. 2005. Aperture pattern and microsporogenesis in Asparagales. Conference proceedings, Monocots III Conference, California, USA (in press)

Penet, L., Nadot, S., Ressayre, A., Forchioni, A., Dreyer, L.L. & Gouyon, P-H. Different developmental ways leading to monosulcate pollen (Examples from the Asparagales). Ann. Bot. (in press).

Roets, F., Crous, P.W. & Dreyer, L.L. Seasonal trends in ophiostomatoid fungal infections of Protea infructescences. S.Afr. J. Bot. (in press).