Tree may reach 18m high with a 3-5 angled trunk. The small yellowish green Flowers lack a perianth and occur in a cyanthium. Fruit is a 3-lobed capsule, which turns red when ripe.
Euphorbia triangularis, Euphorbia evansii.
Common names: River Euphorbia, Riviernaboom, Chandelier Tree.
Family: Euphorbiaceae (Euphorbia family). This family has about 275 genera and 7 500 species. The genera include Alchornea, Croton, Euphorbia, Macaranga, Spirostachys and poinsettia. This family has plants that may be herbs, shrubs or trees and latex is often present. Leaves, when not rudimentary, are usually alternate and simple with free stipules. Inflorescences are situated terminally or axillary. They are mostly in cymes (a broad, more or less flat-topped, determinate flower cluster, with central flowers opening first). They may be grouped in spikes (simple indeterminate inflorescence with sessile flowers on a single unbranched stalk), thyrses (the main axis grows indeterminately, and the branches have determinate growth) or pseudanthia (inflorescences with many flowers appearing as a single flower – like a sunflower). Plants may be monoecious or dioecious and the regular, unisexual Flowers may or not have a perianth. Male flowers have 1-many stamens with free filaments and stamens with up to 4 pollen sacs. Female flowers have a superior ovary with 1-many locules – each with up to 2 ovules. Fruit is a capsule or nut(s). Seeds may have a caruncle (a fleshy structure attached to the seed) and may be poisonous.
Name derivation: Euphorbia Named after Euphorbus: physician to the king of Maurtania (NW Africa) in 10 B.C. triangularis – The ends of stems are triangular in cross section.
Conservation Status: L C. (Least Concern). Assessment Date: 2009 (Raimondo et al.).
This distinctly succulent Tree may reach 18m high. It has with a cylindrical trunk that is slightly 3-5 angled. This shape may extend into branches, which are up to 9cm in diameter, and away from the apex of the plant. The branchlets are usually 3-angled and curve up to form heads at the ends of branches – hence the common name. They are up to 3m long. The paired Spines are situated along the margin on spine shields that may or not link with those above or below. The margin may be wavy. Bark is grey on the main trunk. The branches are green and undergo photosynthesis – replacing leaves for this function.
The Flowers occur in an inflorescence called a Cyanthium (the cup-shaped inflorescence that appears as a single flower, but is actually a collection of reduced flowers). These flowers are unisexual – either Male – with only one stamen; or Female having a single pistil. Here the Ovary usually has three locules and each contains one ovule. The Perianth (sepals and petals) is absent. Coloured, modified bracts and nectar glands attract Pollinators. Cyanthia are bright, yellowish-green, vertically arranged and occur, in dense clusters, just above the spines on the ridges. (Jun-Aug).
The mature, red and woody Fruit is a slightly 3-lobed Capsule (a dry fruit resulting from the maturing of a compound ovary which usually opens at maturity by one or more lines of dehiscence) that is up to 8mm in diameter. It rests on a curved stalk that is up to 6mm long. (Jul-Oct).
Distribution & Ecology
These Trees are located in arid country on rocky hillsides and along tidal rivers just above the riverbanks. Located in the Eastern Cape where it is the most common and here the stem is usually 3-angled. In KwaZulu-Natal, they are usually 5-angled. This plant is located in Mpumalanga, Swaziland and southern Mozambique. Canaries consume the Seeds on the tree and doves eat the fallen seeds.
Propagation is by seeds and cuttings. Note: the Sap is extremely Poisonous.
Boon, R. 2010. Pooley’s Trees of eastern South Africa. Flora and Fauna Publications Trust, Durban.
Coates Palgrave, M. 2002. Keith Coates Palgrave Trees of Southern Africa, edn 3. Struik, Cape Town.
Lawrence, G. H. M, 1951. Taxonomy of Vascular Plants, The Macmillan Company, New York. Tenth Printing 1965.
Palmer, E. & Pitman, N. 1972. Trees of southern Africa, Balkema, Amsterdam, Cape Town.
Schmidt, S. Lotter, M. & McCleland, W. 2002. Trees and Shrubs of Mpumalanga and the Kruger National Park.
van Wyk, B. & van Wyk, P. 1997 Field guide to Trees of Southern Africa, Struik, Cape Town.