New species of Geissorhiza (Iridaceae: Crocoideae) from the southern African winter rainfall zone, range extensions, taxonomic changes, and notes on pollen morphology and floral ecology

Abstract

Field work during the past 15 years has resulted in the discovery of 12 new species of the western southern African genus Geissorhiza Ker Gawl. and range extensions for several more. Following a survey of pollen morphology in the genus, we describe new pollen types in one section each of the two subgenera: five species of section  Ciliatae Goldblatt and two of  section Weihea Eckl. ex Baker have more complex apertures than the plesiomorphic single aperture with a 2-banded oper­culum found in other species. In addition, populations currently referred to the typical white (cream)-flowered  G. inflexa (D.Delaroche) Goldblatt with larger, pink, red or purple flowers, have a third pollen type and are recognized as  G. erosa (Salisb.) R.C.Foster. The new species are G. altimontana from the high Langeberg near Grootvadersbos; G. helmei from the Piketberg; G. lupidosa from the Du Toits Kloof Mtns; G. monticola from the Swartberg; G. platystigma from Darling, north of Cape Town; G. sufflava from the Piketberg; G. tricolor from Riversdale (all subgenus Weihea (Eckl. ex Baker) Goldblatt); and G. cantharophila from the Klein Roggeveld; G. demissa from the Kamiesberg. Gitberg and Cold Bokkeveld; G. exilis from the Waaihoek Mtns in the Worcester District;  G. reclinata from the Swartberg: and G. saxicola from the northern Cedarberg-Pakhuis Mountain complex (all subgenus Geissorhiza). We also report range extensions and provide morphological notes for several species, including  G. monanthos Eckl.. new collections o f w hich show that the inclusion of G. leuisiae R.C.Foster in that species was incorrect and we resurrect the species. The addition of 12 new species and recognition of G. erosa and G. lewisiae bring to 99 the number of species in the genus. New identification keys for Geissorhiza are provided that include all new species. We have also accumulated observations of floral ecology in the genus and integrate them with what is known about this aspect of the biology of Geissorhiza. Unusual strategies include deceptive pollination in G. tulhagh- ensis F.Bolus by tabanid flies and in two species, pollination using empid flies in combination w ith halictid bees