Otholobium outrampsii (Psoraleeae, Fabaceae) – a new species from the Western Cape, South Africa

Otholobium outrampsii (Psoraleeae, Fabaceae) – a new species from the Western Cape Province, South Africa, is described and illustrated. This species is closely related to O. curtisiae but can be morphologically distinguished by it having semi-conduplicate, minutely glandular, softly pilose leaflets (versus flat, prominently glandular, glabrous leaflets); leaflet apex attenuate (versus leaflet apex shortly apiculate); calyx accrescent (versus calyx non-accrescent). The description of this new species further highlights the value of citizen science and by giving it the specific epithet ‘outrampsii’, we honour an incredible group of citizen scientists, namely the Outramps CREW group.


Introduction
Otholobium C.H.Stirt. (Fabaceae: Psoraleeae) is a genus endemic to southern Africa and most diverse in the Greater Cape Floristic Region (GCFR), where over 69 species are known to occur (Manning & Goldblatt 2012;Stirton 1989). This paper describes a highly localised new species, Otholobium outrampsii, from the northern slopes of the Outeniqua Mountains in the Western Cape. It is a prostrate to semi-erect resprouting shrublet up to 20 cm tall with sparsely glandular, green hairy stems bearing semi-conduplicate, minutely glandular, softly pilose, narrowly elliptic to narrowly obovate leaflets with sparsely pilose margins. Inflorescences are terminal, pseudo-capitate and borne on short seasonal shoots and comprising 3-4 triplets of flowers. Fruiting calyces are accrescent.

Etymology
The specific epithet outrampsii honours the members of the Outramps Group of the Custodians of Rare and Endangered Wildflowers (CREW) Programme, who have done much to champion the protection of the rare and threatened plants of the southern Cape, and who made a number of special trips to find flowering material of this rare species.

Diagnostic characters
Otholobium outrampsii is a post-fire resprouter and can be diagnosed by a combination of its prostrate to semierect spreading habit up to 20 cm tall, with scarcely pustulate, greyish hairy branches with persistent stipules, semi-conduplicate spreading minutely glandular, softly pilose, narrowly elliptic to narrowly obovate leaflets with an arching attenuate apex, asymmetrical lateral leaflets shorter than the terminal leaflet, leaflets glabrous except for sparsely softly pilose margins, glabrous when mature, and accrescent calyx with subequal lobes and large broadly lanceolate carinal lobe.

Distribution and habitat
Otholobium outrampsii is a rare and highly localised species known from the farm Paardebont, at the foot of Fouriesberg, west of the Robinson Pass on the northern side of the Outeniqua Mountains (Figure 3). This species occurs between the elevations of 430 and 550 m asl. The vegetation at this location is North Outeniqua Sandstone Fynbos (FFs18) as described by Mucina and Rutherford (2006). It favours dry, rocky and welldrained sandy soil derived from Table Mountain Sandstone in full sun on a southwest facing slope. Flowering only occurs after fire from late September to November.

Conservation status
Otholobium outrampsii is known only from a single location in the Outeniqua Mountains. The population size is estimated to be roughly 100 mature individuals. This species is threatened by the presence and spread of Hakea sericea Schrad. & J.C.Wendl in and around the area from which this species is known. There is a potential threat from Acacia mearnsii De Wild. which is infesting the valley below. As the area is generally poorly explored and, given that the plants are small and inconspicuous when not in flower and only flower in the first year after fire, it is likely that other populations may be present on the surrounding hillslopes.