Gisekia haudica
- Holotype: Ethiopia, M. Gilbert 2081 (holotypus K; isotypi EA, ETH, UPS)
- 1. Gilbert, M. G. 1993: A review of Gisekia (Gisekiaceae). – Kew Bulletin 48(2): 343-356. http://doi.org/10.2307/4117942
Notes
Collections of G. haudica were originally named as G. africana because of the number of stamens and the superficially similar habit of the northern forms of that species. It is restricted to the deep red sandy soils of the Haud in the extreme east of Ethiopia and adjacent Somalia and has been named accordingly. It is very easily distinguished from all forms of G. africana except var. pedunculata by the very prominent dorsiventral wings of the mericarps, very similar to those of G. pharnaceoides var. alata. G. africana var. pedunculata differs considerably in habit, being a much more robust plant with ascending lax terminal cymes. The northern form of G. ajfricana var. africana does have a similar prostrate habit and congested inflorescences but the leaves are distinctly oblanceolate, not linear- oblong, and smaller whilst the fruits show no trace of sutural wings. In habit G. haudica most closely resembles some forms of G. pharnaceoides, particularly the form predominant in West Africa ("G. linearifolia”), but in the Horn of Africa the combination of prostrate habit, linear leaves and very dense umbles of pink flowers are distinctive. G. scabridula, described below, is perhaps the most closely related species overall but this is a larger plant in all parts and is easily distinguished by the presence of a tomentum and by the differently ornamented mericarps.
Diagnosis
G. haudica M. Gilbert sp. nov. a speciebus aliis foliis linearibus, umbellis dense congestis florum roseorum vividorum, pedicellis pedunculos semper superantibus, floribus perfectis, staminibus (10-) 15, mericarpibus semper 5 prominente alatis manifeste diff
Habitat
Very open deciduous bushland with Acacia and Commiphora on deep red "Haud" sands. 350-1200 m.a.s.l.
Description
Prostrate ephemeral, all parts usually suffused with red; stems to 20 cm long. Leaves linear-oblong, 35-50 x 3-5 mm. Inflorescences dense, subsessile axillary umbels; peduncle shorter than pedicels. Fruiting pedicels 4-5-6 mm, curved. Flowers always bisexual. Sepals ca. 2 mm long, bright pink. Stamens 15, filaments expanded and +/- joined at base into groups of 3. Carpels 5. Mericarps heterocarpic, some smooth or obtusely papillate, others with a conspicuous whitish dorsiventral suture-wing ca. 0"5 mm high and minutely spiny sides, occasionally also with a pair of low lateral wings.