Origin and Habitat: Eastern Cape, South Africa. Altitude 120-600 m.

• Euphorbia pentagona Haw. non L.

• Euphorbia pentagona Haw. non L.
• Euphorbia heptagona A.Berger non L.

Description: It is a compact perennial cactus-like shrub with prominent ribs that freely branches above and can grow 2,5- 3 m tall.
Stem: Thin columnar, erect, rebranching often in whorls, 1-4 cm thick, bright glossy green or dark green turning grey with age.
Ribs: 5-6, deeply grooved between, whit shallow tubercles.
Spines: The solitary “spines” are sterile dry peduncles up to 1,5 cm long, each with 2-3 tiny bracts, they are pinkish and finally grey.
Leaves: Up to 4 mm long, liner and early deciduous.
Flowers: The buff-lavender to purplish cyathia are small ( approx 4 mm in diameter) and borne at the branch tips. The are solitary or in 2-3 rayed cymes, peduncles short, often persistent. Nectar glands elliptic, separate.
Fruits: Subglobose, approx 6 mm in diameter, subsessile.

Notes: E. pentagona belongs to the Euphorbia section 19 a large group of spiny shrubs that includes Euphorbia aggregataSN|11431]], Euphorbia enoplaSN|21536]]SN|14279]], Euphorbia mammillaris, Euphorbia anoplia, Euphorbia ferox, Euphorbia heptagona, and Euphorbia polygonaSN|14279]]SN|21536]] which are all similar in form. In particular E. pentagona looks like E. enopla and often the plant sold and labelled E. pentagona .
Remarks: Euphorbia aggregataSN|11431]]SN|21541]] Royle 1836 (Nom. Illeg., art 53.1) is a very different species referable to Euphorbia royleana

Bibliography: Major references and further lectures
1) Urs Eggli “Illustrated Handbook of Succulent Plants: Dicotyledons” Springer, 2002
2) Hermann Jacobsen “A handbook of succulent plalnts: Abromeitiella to Euphorbia” Blandford Press, 1960
3) James Cullen, Sabina G. Knees, H. Suzanne Cubey “The European Garden Flora Flowering Plants: A Manual for the Identification of Plants Cultivated in Europe, Both Out-of-Doors and Under Glass” Cambridge University Press, 11/ago/2011
4) Doreen Court “Succulent Flora of Southern Africa” CRC Press, 01/giu/2000
5) Alain Campbell White, Robert Allen Dyer, Boyd L. Sloane “The succelent Euphorbisae (southern Africa)” Abbey garden press, 1941
6) Werner Rauh “Cultivation and Description of Selected Succulent Plants Other Than Cacti” Smithsonian Institution Press 1984
7) Gibbs Russell, G. E., W. G. Welman, E. Reitief, K. L. Immelman, G. Germishuizen, B. J. Pienaar, M. v. Wyk & A. Nicholas. “List of species of southern African plants.” Mem. Bot. Surv. S. Africa 2(1–2): 1–152(pt. 1), 1–270(pt. 2). 1987.

Cultivation and Propagation: Common and relatively easy to grow plant for pot culture. It grows well in a very draining mineral potting substrate, but it isn't picky about soil. The area where this plant is native receives rains both in winter and summer, so it can be watered moderately all year around (except in the coldest month of the winter, as it rot easily ,especially if over-wet). During the summer, they enjoy average feeding and watering. When dormant in winter, keep it totally dry at or around 4°C, even though it seems to tolerate light frosts well. Mature healthy plants are tough and can also be grown outside where frost is not too severe, but when left out it is more sensitive to frost. They do need a lot of light to keep their compact growth-form, but different clones vary in their tolerance of full sunshine. The plants that are not kept in full sun grow faster, but became untidy and may need support as they get larger, or branches fall off. But if grown in the protection of light shade, the thick purple spines of this low-growing clumping columnar plant have the best colour. Sometimes, in really hot full sun all day long, a plant will bleach out a bit. It soon grows into a large, many stemmed specimen, and it can fill a 30 cm bowl. It is also a prolific bloomer, and makes a spectacular specimen.
Propagation: It is propagated by cuttings or seeds. It branches enthusiastically, and offsets are readily available. If you remove an offset, remember to let it dry for a week or so, letting the wound heal (cuttings planted too soon easily rot before they can grow roots). It is better to wash the cut to remove the latex. The seed can be sown just under the surface in normal seedling trays in a sandy seed mix. Germination usually occurs within 1 - 3 weeks.
Warning: As with all other Euphorbias, when a plant get damaged it exudes a thick white milky sap known as latex. This latex is poisonous and may irritate skin. Pay extreme attention not to get any in your eyes or mouth.
Cultivated plants must be handled carefully.
Uses:
1) The villagers use as fuel the withered stems of Euphorbia pentagona and thorny bushes.
2) It is also a common plant used for making hedges.