Euphorbia subsalsa Hiern (1900: 948)

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 : 218-219

10. Euphorbia subsalsa Hiern (1900: 948) .

Type:— ANGOLA. Moçamedes distr.: Pedra de Sal between Moçamedes and Bumbo, Rio Maiombo (Giraul), 3 October 1859, Welwitsch 642 (holotype BM!, isotypes K!, LISU!).

Discussion:— Leach (1976) recognized two subspecies of E. subsalsa , namely subsp. subsalsa from southern Angola and subsp. fluvialis from southern Angola and northern Namibia. Both were said to share features of branches <15 mm thick and the suberect, concave cyathial glands.

Subsp. subsalsa ( Fig. 10 ) is now known to be widely distributed in the coastal parts of southern Angola from Benguela southwards to near Pediva and eastwards to between Oncocua and Iona, close to the Cunene River. This is a somewhat wider distribution than Leach (1976) gave. Here the plants branch mainly from the base, the often straggling, spreading 4-angled branches are 8–16 mm thick and they are mostly marked with pale streaks between the angles, the spines are 6–19 mm long, with the stipular prickles 1.5–5 mm long. The spine-shields become very slender below the spines and taper off to leave a gap of 3–5 mm above the next axillary bud. Leach (1976) considered that erect and concave cyathial glands were typical for subsp. subsalsa , since they were shown like this in a sketch made from the type ( White et al. 1941: fig. 884). However, this was made from dried material. Living plants have spreading glands that vary between slightly concave, flat and slightly convex above ( Fig. 10 D, E ) and they are yellow, greenish yellow to brownish yellow ( Bruyns 2018: fig. 37). The female floret is sessile ( Fig. 10 G ).

Subsp. otzenii Bruyns (2018: 52) is endemic to an area south of Kaoko Otavi in the Kaokoveld of Namibia. It differs from subsp. subsalsa by the uniformly grey-green branches and the shorter spine-shields (only 2−4 mm long below the spines). From E. schinzii it is mainly distinguished by the shorter bracts and the slightly concave upper surfaces of the cyathial glands.

Figures

FIGURE 10. Euphorbia subsalsa subsp. subsalsa. A, B, young spines and leaf-rudiment from above (scale 2 mm, as for B–E). C, young spines and leaf-rudiment from side. D, side view of cyme in first male stage. E, side view of cyathium in female stage. F, anther and bracteole (scale 1 mm, as for G). G, female floret. Drawn by P.Bruyns from:A–F, Bruyns 10402 (BOL), 10 km towards Sao Nicolau, north of Namibe, Angola; G, Bruyns 10742 (BOL), 48 km north of Lucira, Angola.