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
Highlights
Geissorhiza Ker Gawl., with 99 species, is a large genus o f Iridaceae subfamily Crocoideae Bur nett centred in the southern African winter rainfall zone (Goldblatt 1985; Goldblatt & Manning 2000a; Manning et al 2002) and largely confined to the Cape floristic region
We provide new keys to the two subgenera o f Geissorhiza (A ppen dix 1). w hich accom m odate all species described since the publication o f the last revision o f the genus (G old blatt 1985)
In an effort to determine the extent o f the variation in pollen morphology in the genus, we have surveyed a wide range of species belonging to both subgenera and all sections (Table 1)
Summary
Geissorhiza Ker Gawl., with 99 species, is a large genus o f Iridaceae subfamily Crocoideae Bur nett centred in the southern African winter rainfall zone (Goldblatt 1985; Goldblatt & Manning 2000a; Manning et al 2002) and largely confined to the Cape floristic region (as defined by Goldblatt & Manning 2000a). Ex Baker) Goldblatt and five of subgenus Geissorhiza. While monosulcate grains with a 2-banded operculum are typical of Crocoi deae (Goldblatt et al 1991) and o f Geissorhiza, the two species G. heterostvla L.Bolus and G. inflexa (D.Delaroche) Ker Gawl. Instead o f the single, elliptic aperture, these species have a more complex condition with multiple apertures, described in detail below Discovery o f these striking pollen grains led us to examine a range o f spe cies o f the genus. Geissorhiza com prises 99 species, all occurring w ithin the Greater Cape Floristic Region (sensu Bom et al 2006) w ith only G. hracteata extending outside its confines. TABLE 1.— Classification o f Geissorhiza species arranged by subgenus and section including new species described here, based on Goldblatt’s (1985) infrageneric classification. Pollination primarily by hopliine scarab beetles is rare, and is reported for the first time in the genus, as are visits by empidid tlies (Empididae), and deceptive pollination by short-proboscid Tabanidae
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