New species and notes on Hesperantha (Iridaceae) in southern Africa

Abstract

Field studies of the sub-Saharan African and largely southern African Hesperantha conducted since 2003 have resulted in the discovery of three new species in this genus, bringing the total to 82. Hesperantha longistyla J.C.Manning & Goldblatt. known from one collection from the mountains of SW Namibia, is a dwarf plant with moderately long-tubed, purple flowers and unusually long style branches, possibly allied to the Kamiesberg species,  H. latifolia. A second species,  H. helmei Goldblatt & J.C.Manning, also known from a single collection from the interior mountains of Eastern Cape near Graaff- Reinet, has terete leaves and small flowers with tepals ± 8 x 2.5 mm, about as long as the perianth tube. It is apparently most closely allied to the Roggeveld species, H. cliolata. A third novelty, H. lithicola J.C.Manning & Goldblatt. restricted to the Swartruggens range in the eastern Cold Bokkeveld, has bell-shaped corms with toothed margins, leaves 1-2 mm wide, and white flowers with a tube 10-12 mm long, and appears most closely allied to the widespread H. falcata. A new collection of H karooica from northeast of the Hantamsberg represents a small but significant range extension for this local endemic previously known from just two collections near Calvinia, south of these mountains. The flower size, especially dimensions of the tepals, confirms its status as a separate species allied to H. vaginata. Lastly, new collections o f the relatively uncommon, yellow-flowered variant of H. acuta show that this plant, confined to the eastem portion of the range of the species, differs consistently from the white-flowered form in several floral features, and it is raised to subspecies rank as H. acuta subsp.  tugwelliae.