Euphorbia triaculeata Forssk.
Euphorbia faurotii Franch., E. infesta Pax, E. triacantha Ehrenb. ex Boiss.
Monoecious shrub, cactiform, up to 1.2 m tall. Branchy, narrow ascending stems (5-10 mm thick), with a stellate section with 3-5(7) angles that are sometimes very prominent; with 3 or 5 spiral rows of tubercles. Shield from which the spines arise, narrow 6-10 mm; well developed stingers, 1.5-3.5 mm long, arranged in even pairs; solitary spine (actually the result of the union of a pair of spines) 12-27 mm long, reddish when at the beginning of development and reflex inclination in juvenile stems. Inflorescence in the axils of the spines, solitary, 4-5 mm long and pedunculated (peduncle c 1.5 mm); funnel-shaped cyatio, c 2.5 x 4 mm; glands united in a spreading edge. entire or divided into 5-6 lobes, rarely partially free, surrounding 5-6 transversely rectangular or subquadrate lobes. The glands are extended, contiguous, red or yellow to pink. The fruit is a capsule that does not protrude from the involucre, 3 x 4.5 mm, straw-colored, roughly angled. Seed subglobose, c 1.7 mm in diameter, prominently rough-papilose, without caruncle.
Flowering:
No data for this region
Fruiting:
No data for this region
Habitat:
Rocky slopes and sand dunes in coastal regions, altitude does not usually exceed 350-400 m. Near the marine coast it forms communities that replace the halophilous species.
Distribution:
Central and southern coast of the Red Sea, both Asian (Saudi and Yemeni coasts) and African (Djibouti, Eritrea and Sudan coasts (confirmed in Suakin, probably more widespread). There are numerous sheets attributed to this species in Somalia, but its presence in said country is denied by the authors of the flora of the same.This herbarium material would deserve a thorough review.
Observations:
The existence of a pair of well-developed stingers, together with solitary spines, differentiates it from the rest of the catiform euphorbias of North Africa, in fact, this trio of defensive structures gives its name to the species and at one time it was thought that such rarity, justified separating it into its own subsection (subsec. Triaculatae). Currently, the importance of having three “skewers” has been downplayed and is included in subsec. Euphorbia, along with the other North African cactiforms.
Conservation status:
Rare but widely distributed species, it is not considered threatened. Currently, it has not been assessed at a global level in the IUCN Red List of Threatened Species. Cactiform euphorbias are included in Annex II of CITES.