A taxonomic revision of the section Myrrhidium of Pelargonium (Geraniaceae) in southern Africa

A multidisciplinary approach was followed in this revision of the section Myrrhidium DC. Besides the morphology, the anatomy of the leaves, pollen and chromosomes were studied in order to delimit the taxa and to determine their relationships. Six species, six subspecies and four varieties are recognized. P. longicaule Jacq. var. angustipetalum Boucher is described as a new taxon and several new combinations are made. The diagnostic features of the section are the heteroblastic leaves, extremely zygomorphic flowers with prominently raised veins on the sepals, four to five petals and five or seven fertile stamens. The floral structure indicates that the section Myrrhidium is an advanced one and that it is closely related to the section Jenkinsonia (Sweet) Harv