Three new species of Diascia (Scrophulariaceae) from the Western Cape, South Africa

K E Steiner

doi:10.4102/abc.v39i1.226

Abstract

Three new annual species of Diascia Link Otto are described from the Western Cape Province of South Africa. D. collina is characterized by greyish magenta flowers with two divergent yellow sacs containing oil-secreting trichomes. It is restricted to granite outcrops in the vicinity of Saldanha Bay, from the West Coast National Park and Langebaan north to Vredenburg. D. pusilla is closely related to D. collina. but differs from that species in having smaller flowers with shorter, ± parallel sacs, and posticous filaments that lack a protuberance where they bend sharply backwards towards the upper lip. It occurs in grey to whitish sands usually near seasonally moist or wet areas. It has not been found more than 35 km from the coast and ranges from Modderrivier, south o f Darling, north to Lambert’s Bay. D. appendiculata is related to D. diffusa (Thunb.) Benth. and is characterized by having small, mainly reddish lilac to greyish magenta flowers, two shallow depressions in the corolla tube at the base of the upper lip, and posticous filaments with sterile appendages. It is known from only six localities in the general vicinity of Citrusdal and occurs in fynbos vegetation on lower mountain slopes or flats, in loose alluvial sands derived from Table Mountain Sandstone.

Highlights

Diascia Link & Otto is a genus of ± 72 species of annual and perennial herbs endemic to southern Africa
Section Racemosae was revised by Hilliard & Burtt (1984) and three additional taxa were described more recently (Steiner 1989, 1999)
Section Diascia has not been revised since Hiem’s (1904) treatment in Flora capensis, many new species have been described in recent years as part of a revisionary study (Steiner 1992a, b, c, d 1995)