Salvia plebeia R. Br.: taxonomy, phytogeography, autogamy and myxospermy.

Different attributes of the remarkable Salvia plebeia R.Br. (Lamiaceae) are reviewed. Its range is from Iran throughout Asia to Australia. The curious distribution disjunction of c. 4000 km between SE Asia and E Australia and its status, native or introduced, are discussed. The name is here typified with a specimen from Australia. In Asia, S. plebeia almost always grows in secondary habitats. In Australia, where it is the only representative (excluding aliens) of the genus, it usually grows in undisturbed habitats. Everywhere, it is remarkably oligomorphic. It has some of the smallest corollas in the genus and our observations showed that it is frequently autogamous, a rare occurrence in Salvia. Using innovative SEM technology, the mucilage produced by wetted nutlets was studied. Pollen from four separate areas of its range was examined with light microscopy and SEM. In both these investigations, and the morphological ones, we did not detect significant differences to support recognizing infra-specific taxa the species merits a broad-based molecular analysis.