TWO NEW SPECIES OF OSTEOSPERMUM ( COMPOSITAE–CALENDULEAE ) FROM SOUTHWESTERN CAPE PROVINCE, SOUTH AFRICA

The tribe Calenduleae of the Compositae ( Asteraceae ) has a pronounced centre of diversity in South Africa, particularly in Cape Province. The largest genus, Osteospermum L., contains c.50 species in Africa and southwestern Arabia, including about 40 in Cape Province. Two new species are described here, both narrowly endemic in southwestern Cape Province. Osteospermum australe is confined to lowland coastal limestone areas in Bredasdorp district, whereas Osteospermum burttianum has a restricted distribution in the Langebergen mountains in Heidelberg district. lobes ovate-oblong, 1.5–1.8mm long, apically crested and acute, without midvein, with lateral marginal veins connecting at the sinuses and continuing down the corolla. Anthers 2mm long, base caudate, apical appendage triangular-ovate. Style simple, sterile, apically tipped with a shortly bilobed obtuse cone surrounded by a fringe of short pili. Ovary narrowly oblong, 1.5–2.5mm long, glabrous, 2-veined. Additional specimens examined . S OUTH A FRICA , C APE P ROV . Swellendam Div., S slopes of Naauwkransberg in the Langebergen near Heidelberg, 3000–4000ft., 28 iii 1948, E. Esterhuysen 14426 (BOL, K); Warmwaterberg 3320 DD, Langeberg East MCA, Horingberg, vertical slope, S aspect, 1000–1300m, 8 i 1987, T.J. van der Merwe 175 (NBG, PRE); 3320 CD, Langeberg, trail 15F in Protea Valley between Warmwaternek and Protea Valley hut, S slope of second mountain range in deep kloof, 1000m, 3 v 1987, J.L. du Plessis 22 (NBG).


INTRODUCTION
Ongoing studies in the small tribe Calenduleae (Compositae) suggest a number of taxonomic changes. The tribe was thoroughly studied by Tycho Norlindh (1906-1995; in a series of papers he presented a useful account particularly of the South African members (Norlindh, 1943(Norlindh, , 1960(Norlindh, , 1977. However, recent research findings, including molecular data, suggest a revised generic taxonomy (cf. Nordenstam, 1994aNordenstam, ,b, 1996Wood & Nordenstam, 2003). New herbarium accessions and better field observations are also destined to modify and refine Norlindh's taxonomy at species level (Nordenstam & Wood, in prep.). Two distinct new species of Osteospermum L. are described here.

Derivation. Named for its location at the southernmost point of Africa.
Distribution and ecology. Restricted to coastal and lowland limestone in the vicinity of Cape Agulhas, the southernmost tip of Africa. The population found by me in 1962 was quite small and limited to a low limestone ridge in a low-growing fynbos community with Aspalathus incurvifolia Vogel ex Walp., Erica longifolia Donn, Felicia nordenstamii Grau (type locality), Pelargonium betulinum Aiton, Adenandra obtusata Sond. and species of Protea, Mimetes and Gladiolus.
Conservation status. A local and apparently rare species endemic to lowland limestone. It is nowhere abundant and possibly threatened or endangered. An attempt in 2002 to find it again in the type locality was unsuccessful (Alan Wood, pers. comm.).
Osteospermum australe is a small shrub with closely set leaves, which are entire with distinct cartilaginous and scabrid margins. The upper leaves, particularly on flowering branches, are imbricate and distinctly margined. The large and more or less sessile capitula have numerous conspicuous rays and the involucre is at least partly covered by the dark-margined upper leaves. There is some variation in size of leaves and capitula; the specimens from Pearly Beach are larger than the type collection from Cape Agulhas, but there is no doubt that they are conspecific (Fig. 1A,B).
Osteospermum australe is a very distinct species apparently without close relatives. Osteospermum imbricatum L., as the name implies, also has imbricate leaves which are, however, much smaller, and its capitula are small and distinctly pedunculate. Osteospermum rotundifolium (DC.) T. Norl. is very different in leaf shape and synflorescence, with several small pedunculate capitula.
lobes ovate-oblong, 1.5-1.8mm long, apically crested and acute, without midvein, with lateral marginal veins connecting at the sinuses and continuing down the corolla. Anthers 2mm long, base caudate, apical appendage triangular-ovate. Style simple, sterile, apically tipped with a shortly bilobed obtuse cone surrounded by a fringe of short pili. Ovary narrowly oblong, 1.5-2.5mm long, glabrous, 2-veined.  Distribution and ecology. Apparently endemic to the Langebergen near Heidelberg, an area recognized as a local centre (or subcentre) of endemism within the Cape Floristic Region (Weimarck, 1941;Goldblatt & Manning, 2000;van Wyk & Smith, 2001). Osteospermum burttianum grows as a compact or somewhat diffuse rounded shrub on steep slopes and south-facing cliffs at altitudes above 1000m. It occurs in mountain fynbos with Restio Rottb., etc. on sandstone derived soil (TMS).

Conservation status.
A species with restricted distribution in a mountainous habitat. It may be safe in some steep cliff habitats, but might be regarded as vulnerable because of its limited distribution and proximity to some popular walking trails and hiking areas.
Osteospermum burttianum is related to O. polygaloides L., which though variable, is never as large-leaved as the new species and has a different habit, not being cushionshaped. The capitula of O. polygaloides are distinctly smaller with less conspicuous rays.

A C K N O W L E D G E M E N T S
I wish to thank Nicholas Hind and Lawrie Springate for useful reviewing and Crinan Alexander for pertinent editorial comments.