Floral ontogeny, petal diversity and nectary uniformity in Bruniaceae

Abstract

Bruniaceae are a small family subendemic to the Cape Floristic Region. Flowers are actinomorphic, choripetalous, pentamerous and tetracyclic. The petals show diverse adaxial swellings, which have been quoted as an example of diplophylly. Developmental studies confirm the true choripetaly of the flowers, thus pointing to an affinity to the Apiales within the euasterids II. They reject, however, the hypothesis of diplophylly as the petal swellings grow out rather late and are not vascularized. According to the position, size and shape of the swellings, six petal types are distinguished, which in part have phylogenetic information. Nectaries occur on the upper part of the ovary. Nectar is exuded through modified stomata serving as secretory channels. All genera have gynoecial nectaries of the mesenchymatous type. © 2006 The Linnean Society of London.