Euphorbia kaokoensis (A.C.White, R.A.Dyer & B.Sloane) Leach (1976: 33)

Bruyns, Peter V., Klak, Cornelia & Hanáček, Pavel, 2020, A review of the Euphorbia schinzii-complex (Euphorbiaceae) in southern Africa, Phytotaxa 436 (3), pp. 201-221 : 208

3. Euphorbia kaokoensis (A.C.White, R.A.Dyer & B.Sloane) Leach (1976: 33) . Euphorbia subsalsa var. kaokoensis White et al. (1941: 965) . Type:— NAMIBIA. Kaokoveld: Kauas Okawe, 28 November 1939, Hahn sub Otzen 3 (holotype PRE!).

Discussion: — Euphorbia kaokoensis is endemic to the Kaokoveld of north-western Namibia and is closely allied to E. otjipembana . In E. otjipembana the branches are thicker and 4- to 6-angled and are less strongly spined (the branches are more slender, more sharply spined and with better developed stipular prickles in E. kaokoensis ). Florally, with its quite thin, erect and somewhat pinkish cyathial glands, E. kaokoensis is most similar to subsp. fluvialis (and less so to subsp. otjipembana ). Euphorbia kaokoensis and subsp. fluvialis differ in that in subsp. fluvialis the plant is taller, with the branches more erect from their bases and always 4-angled. In his key, Leach (1976: 6–7) placed subsp. fluvialis under ‘branches <15 mm thick’ and E. kaokoensis among those with ‘branches> 15 mm thick’. However, in subsp. fluvialis they are 15−30 mm thick and in E. kaokoensis they are 15−25 mm thick.