The Indigofer a filifolia complex ( Fabaceae ) in southern Africa

The Indigofera filifolia Thunb. complex, previously known as a widespread polymorphic species, is segregated into three species. / . filifolia is retained as a variable species and two allied species, /. gifbergensis C. H. Stirton & J. K. Jarvie and I. ionii J. K. Jarvie & C. H. Stirton are described as new.


INTRODUCTION
The pantropical genus Indigofera comprises some 800 species.It forms a large and distinctive part of the tribe Indigofereae which also contains two closely related genera Cyamopsis and Rhynchotropis along with an anomalous Madagascan genus Phylloxyon (Polhill 1981).
Indigofera was once the main source of indigo dye but its importance dwindled as cheaper synthetic analogues were developed to replace the plant source of the dye.There is, however, a renewed interest in the genus and it has begun to be of some value as a source of forage legume (De Kort & Thijsse 1984).
The last major revision of Indigofera in Africa was by Gillett (1958), who recognized 278 species.He divided the African representatives into 5 subgenera, 5 sections and 19 subsections.As this revision was a precursor to a revision of the genus for the Flora o f Tropical Exist Africa he treated only 70 species in any detail.The work is essentially regional and ignores to a considerable ex tent areas such as southern Africa.
The present investigation focuses on the widespread polymorphic species /. filifolia in South Africa.Gillett (1958) placed I. filifolia Thunb.as the sole member of his section Juncifolieae.His diagnosis is limited to the presence of petioles many times longer than the small terminal leaflet, persistent when the latter falls off; fruit ing pedicels erect and spreading; and endocarp spotted with seeds ± separated.
Indigofera gifbergensis is restricted to mountainous regions from Kobe Pass in the north to Cedarberg Sneeukop in the south (Figure 2).This mountain fynbos endemic flowers from late August to November.It occurs between 600-1 650 m.This distinctive species is easily separated from I. fili folia and I. ionii by its stiff compact habit, small brickred flowers, the absence of tufts on anthers and its blotched seeds.
Seeds oblong, 2-3 x 2 mm, olive-green.Figure 3. Indigofera ionii is restricted to the mountains of the south-western Cape (Figure 4).This fugitive fynbos species favours damp areas, usually on tussocks in river beds, vleis and marshes.It flowers sporadically from August to April, with peaks between September and Jan uary.It occurs from 500-700 m.
Indigofera filifolia is a widespread fynbos endemic occurring from the Cape Peninsula eastwards to Heidel berg (Figure 2).It favours damp sites and is especially common along watercourses.The plants flower through out the year but with a peak from February to March.This species coppices strongly after bums.