Systematics and phylogeny of the Satyrium erectum group (Orchidaceae), with descriptions of two new species from the Karoo region of South Africa

Abstract

Two spectacular new orchid species from the semi-arid Karoo region of South Africa are described here. Both have been confused with Satyrium erectum Sw. in the past, yet have clear diagnostic characters which justify their recognition as distinct species. Satyrium pulchrum S. Johnson & Kurzweil sp. nov., known only from an isolated granite inselberg in Namaqualand, appears to be the sister taxon to S. erectum, whereas Satyrium pallens S. Johnson & Kurzweil sp. nov., known from several populations along the southern margins of the Karoo, has closer affinities to Satyrium longicolle Lindl. These four species form a distinct monophyletic group characterized by several synapomorphies. The allopatric distribution pattern and considerable divergence in floral characters of the sister species suggest that speciation involved shifts in the pollination system of geographically isolated populations. (C) 1998 The Linnean Society of London.