General Info

Leafless Tree up to 10m high with poisonous latex. Stem ends in much branched apex.  Very reduced, regular, unisexual Flowers in a cyanthium. Fruit:  dehiscent red capsule.

Description

RSA Tree No. 345.

Common names: Lebombo Euphorbia, Lebombo-naboom.

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 (NW Africa). confinalis – on the boarder – distribution between RSA and neighbouring countries. There are more than 300 species of Euphorbia in the RSA.

Conservation Status: L C. (Least Concern). 2009 (Raimondo et al.). In Zimbabwe it is considered vulnerable.

Tree

The sturdy Tree is up to 10m high and shaped somewhat like a “disguised” cell phone mast. Each year the Lower branches are shed resulting in the unbranched Trunk. The Apex ends with a smallish crown. The grey to brown Bark is rough. Branches tend to point upwards and are up to 7cm wide. They usually have 3 or 4 vertical Wings present. Smaller branches tend to be square in cross section. Simple paired Spines are up to 7mm long and are only present in younger parts. They arise on horny bases called Spine shields. In this plant, the spine shields are stout, conspicuous and may be united. Milky caustic Latex is present. It is very poisonous – causing blistering, allergic reaction or even blindness. Plants are succulent and cactus like but the true cactus lacks the paired spines and the caustic latex that is present in this Euphorbia.

Leaves

The Leaves are either absent or fall early. This is a possible adaption to the dry environment. The Stems can photosynthesise.

Flowers

The small, greenish-yellow to yellow Flowers are situated just above the spines on the wing ridges. They occur in a flower like structure / inflorescence called a Cyanthium (cyathia – false flower is a euphorbia inflorescence). They usually have 5 joined bracts outside. There are up to 10 brightly coloured nectar glands occurring at the cyanthium rim, which may have petal like appendages or brightly coloured bracts followed by the much-reduced male flowers at the base of each bracteole. In the centre is a much-reduced female flower that is composed of a unisexual flower surrounded by bracts and often glands. The Male flowers are reduced to a single Stamen. They occur in groups surrounding the female flower. The Theca (pollen sacs) are longitudinally dehiscent. The Female flowers are solitary within the Involucre (bracts forming one or more whorls at the base of, or below, the very compact or reduced flowerhead). There is no Perianth (the 2 floral envelopes considered together; a collective term for the calyx and corolla) present. The reduced or stalked Ovary has 3 Styles. The Ovary usually has 3 Locules (compartment within an organ e.g. ovary, anther or fruit) each having a single pendulous ovule. The flowers are insect Pollinated. (May-Aug).

Fruit

The dehiscent, 3-lobed, deep-red 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). The capsule occurs at the end of a long stalk, is up to 10mm wide and woody when mature. The capsule opens along the inner face to release the Seeds. (Jul-Oct).

Distribution & Ecology

The Trees usually occur at an altitude of between 300m and 400m, on rocky outcrops, in deciduous woodlands e.g. the Lebombo mountain range generally, and on alluvial soil in southern Mozambique. It is mainly found in dry areas. Examples are visible at Nkumbe View Site – south of Tshokwane in the Kruger National Park. Their growth form enables conservation of water. The stems – especially the younger ones are photosynthetic and compensate for their lack of leaves. Birds feed on the Fruit.

Ethnobotany

Trees can be grown from Seed or Truncheons (stem cutting from a selected plant – used to produce genetically identically new plants) but must not be over-watered. Due to the poisonous sap / latex this plant must be handled with care. The latex is used to stun fish. Do not use fallen wood for making a braai – the consequences could be very serious.

References

Coates Palgrave, M. 2002. Keith Coates Palgrave Trees of Southern Africa, edn 3. Struik, Cape Town. p526.

Lawrence, G. H. M, 1951. Taxonomy of Vascular Plants, The Macmillan Company, New York. Tenth Printing 1965. p565.

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. p280.

van Wyk, B. & van Wyk, P. 1997 Field guide to Trees of Southern Africa, Struik, Cape Town. p38.

http://redlist.sanbi.org/species.php?species=574-923

http://www.llifle.com/Encyclopedia/SUCCULENTS/Family/Euphorbiaceae/21567/Euphorbia_confinalis

http://www.zimbabweflora.co.zw/speciesdata/species.php?species_id=135780

http://www.africaimagery.com/image_gallery/album/Destinations/South%20Africa%20-%20Mpumalanga/slides/490712.html

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