General Info

Tree is up to 10m+ high. All Leaves deciduous & fall very early. Flowers on wing ridges in cyanthia. They have 1 stamen or 1 pistil. Fruit is a small globose, woody capsule.

Description

Euphorbia ingens, Euphorbia cooperi, Euphorbia Natalensis, Euphorbia similis.

RSA Tree No. 351.

Common names: Cactus Euphorbia, Candelabra Euphorbia, Candelabra Tree, Common Euphorbia, Tree Euphorbia, Lebombo-naboom, Naboom Euphorbia.

Family: Euphorbiaceae (Euphorbia family e.g. exotic poinsettia – Euphorbia pulcherrima). This family has about 275 genera and 7 500 species. Our local genera containing trees include Alchornea, Croton, Euphorbia, Macaranga and Spirostachys. 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 (inflorescence with many flowers appearing as a single flower – like a sunflower). In Euphorbia they appear as cyathia (where they usually have 5 joined bracts outside: up to 10 brightly coloured nectar glands which may have petal-like appendages or brightly coloured bracts followed by 5 much reduced male flowers at the base of each bracteole. In the centre is a much-reduced female flower). 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: Euphorbiaafter Euphorbus (50BC-AD19): physician to the king of Mauretania. ingens – huge – referring to the massive, much-branched rounded crown. The Genus Euphorbia has in excess of 300 species in southern Africa.

Conservation Status: L C. (Least Concern). 2009 (Raimondo et al.).

Tree

This sturdy, up to 10+m high Tree has a massive, sturdy, rounded crown. Its shape has been compared to a hot-air balloon. The erect and reasonably persistent Branches are fairly dense and originate reasonably low-down. The lower branches do not die down annually as they do in some Euphorbia sp. They thus grow forming the hot air balloon shape. Branchlets (a small branch or division of a branch especially a terminal division); usually applied to branches of the current or preceding year) have 4-5 angled wings and are up to 12cm in diameter. These branchlets are constricted to form segments. Simple paired Spines are and up to 5mm long or absent – especially in old trees. They arise on horny bases called Spine shields. In this plant the spine shields are separate and are often in hollows on the wing margins. There is no continuous shield ridge. Milky, caustic Latex is present. These plants are succulent and cactus like, but the true cactus lacks the paired spines and the toxic latex present in this Euphorbia. Euphorbia cooperi is similar but smaller and the branches are 5-6 angled.

Leaves

The deciduous tree has very early falling Leaves that are oblanceolate (the reverse of lanceolate, as leaf broader at the apical third than at the middle and tapering towards the base). They may be up to 8cm long in very young plants only.

Flowers

The small and yellow-green Flowers are situated on the wing-ridges, just above the spines, reasonably close to the branch-ends. Flowers are monoecious (separate male and female flowers present on the same tree). Flowering branches are green with wing-like angles that are constricted into segments that are up to 8cm long and broadest in the centre. They occur in an inflorescence called a Cyanthium (the name given to the cup-shaped Euphorbia inflorescence that appears as a single flower but is, in fact, a collection of reduced flowers). Sepals and Petals are absent. These flowers are unisexual – either male or female. The Male flowers are reduced to a single Stamen with one Filament that ends in a 2-thecous (with 2 pollen sacs) Anther. This anther dehisces longitudinally. Many such male flowers surround the single female flower. The Female flower has a the single Pistil with a stalked, superior Ovary that has 3 locules, each containing a single pendulous Ovule. There are usually 3 Styles and 3 Stigmas present. Pollinators are insects that are attracted by surrounding coloured, modified bracts and nectar glands. (Mar-Jul).

Fruit

The smooth, dehiscent, 3-lobed, globose (spherical or nearly so), reddish Fruit is  a Capsule (a dry fruit resulting from the maturing of a compound ovary which usually opens at maturity by one or more lines of dehiscence). It is up to 1cm wide and situated at the end of a stout stalk. When Mature it becomes purplish and woody. (Jul-Oct).

Distribution & Ecology

These plants are usually occur at an altitude of between 300 and 1 500m. They are common on rocky outcrops, in deciduous woodlands and often close to termite mounds. Provinces where they occur include KwaZulu-Natal, Gauteng, Mpumalanga, Limpopo, North West. They are also occur in Swaziland, Zimbabwe, Mozambique and northwards into Tropical Africa. This is the most photographed Euphorbia species in the RSA. The growth form enables these trees to conserve water and their lack of leaves is compensated for by the stems – especially the younger ones being photosynthetic. These Euphorbias are one of the few plants that use 3 different photosynthesis mechanisms. An “unusual” one of these is CAM photosynthesis (Crassulacean acid metabolism – here the stomata (structures utilising 2 guard cells which, unlike lenticels, can control the gaseous exchange between the plant and the surrounding atmosphere) only open at night to preserve moisture. During this dark period, they collect and store carbon dioxide to use during the daylight for photosynthesis). Birds, like the Black-collared Bulbuls, Crested Guineafowl, Emerald-spotted Wood Doves, Franklins and Turtle Doves feed on the Fruit. Old Wood is used by Woodpeckers for nesting. The Roots are eaten by porcupines and cane-rats. Flowers, including buds are eaten by vervet monkeys.

Ethnobotany

This tree can be Grown from seed or truncheons. These should not be over-watered in winter. Due to the poisonous milky sap / latex, great care should be taken when handling this plant. The Latex is very poisonous – causing blistering, allergic reaction or even blindness. Latex is used to stun fish. Prior to cutting, the tree is often subjected to fire which decreases the effect of the toxic sap. This heating method is also used with the Tamboti trees. The Wood has a low density, is tough and is used for making boats, planks and doors.

References

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. p1171

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. p38.

 

https://en.wikipedia.org/wiki/Euphorbia

www.plantzafrica.com/plantefg/euphorbingen.htm

https://en.wikipedia.org/wiki/Euphorbia_ingens

http://www.operationwildflower.org.za/index.php/plant-records/euphorbias/114-euphorbia-ingens

http://posa.sanbi.org/flora/browse.php?src=SP