Spineless, medium sized Tree with papery flaking bark. Coppery bark peels off revealing dark green underbark. Imparipinnate Leaves are long. Dioecious, 4-merous Flowers are in panicles. Fruit is a 1-Seeded drupe.
Commiphora harveyi, Protium africanum, Balsamea harvyi.
RSA Tree No. 277.
Common names: Red-stem Corkwood, Red Paperbark Corkwood, Cork Tree, Copper-stem Corkwood, Harvey’s cork tree.
Family: Burseraceae (The torchwood family, which include frankincense from Boswellia sacra, myrrh from Commiphora myrrha both of which have an incense like odour). Non-allergenic resin occurs in most plant tissues. Worldwide there are about 16 genera and in excess of 500 species, which occur in tropical South America, Malaysia and Africa. In the RSA Commiphora is the only genus and there are about 20 species that may be regarded as trees. The Bark is smooth, aromatic and pealing or flaking. The Leaves are resinous and usually without stipules. The usually dioecious Flowers have 4 or 5 petals and sepals that are imbricate (having regularly arranged, overlapping edges, as roof tiles). Flowers are actinomorphic (regular, symmetric) and have Stamens are double or equal the number of petals. The superior Ovary has 3-5 carpels with 2 ovules in each and the single Style ends in a capitate (forms like a head) or lobed Stigma. The pitted Fruit is often an edible drupe.
Name derivation: Commiphora Greek: kommi – gum and phora – bearer. harveyi – named after W.H. Harvey (1811-1866) an Irish botanist and editor of the first 3 volumes of Flora Capensis (a systematic description of the plants of the Cape Colony, Eastern Cape, & Port Natal).
Conservation Status: L C. (Least Concern). 2009 (Raimondo et al.).
No spines are present on this Tree, which may be up to 20m high. However, it is usually a much smaller, squat tree up to about 7m high. The green smooth Trunk may appear succulent. The Bark usually peels or flakes off in large copper-coloured papery flakes or in thick discs. This reveals the dark green, photosynthetic underbark tissue. There are odoriferous Resin ducts present in the bark from which resin and sap flows when bark is damaged. Young Branchlets are fluted (grooved, funnelled or channelled) and have visible pale lenticels (usually raised corky oval or elongated areas on the plant that allow the uncontrolled interchange of gases with the environment). These small branches do not end in spine tips.
This tree may be without Leaves for months. When they appear, they are clustered at the ends of branchlets. Leaves are large – up to 20cm long. The tree is deciduous and the compound leaves are imparipinnate (pinnately compound leaf ending in a single leaflet). There are usually 1-3 pairs of Leaflets and the terminal one. The leaflets are thin and turn bright yellow before they fall. Leaflets are up to 8 x 3cm and may be lanceolate (lance-shaped) or ovate (egg-shaped) or elliptic. They are dark green and shiny. The Leaflet Apex tapers and may end in a drip-tip and the Base tapers. Leaflet Margins may be scalloped to serrate (saw-toothed margin with teeth pointing forward). The Petiole (leaf stalk) is purplish red when young and up to 6cm long when mature. Petiolules (leaflet stalks) are up to 1,5cm long. Stipules (basal appendage of the petiole) are absent.
The dioecious (having male and female parts on separate plants) Flowers are borne in panicles (indeterminate, branched inflorescence with stalked flowers) up to 15cm long. The yellow to green flowers are small, cup-shaped and actinomorphic (Regular, symmetrical. The perianth, the calyx and corolla, can be divided into 3 or more identical sectors) and carried in axillary sprays on young wood. They are attached by pedicels (stalk of a single flower) that are up to 15cm long. The Calyx, which is funnel shaped, has 4 persistent Sepals which are united at the base. The Corolla, in this bell-shaped flower, has 4 whitish Petals that alternate with the sepals. A cylindrical Disc (a more or less fleshy or elevated development of the receptacle) is present. The Male flowers are usually larger than female flowers. Here there are 4 Stamens present. They have introrse (turned or faced inward or toward the axis as in an anther whose line of dehiscence faces towards the centre of the flower) Anthers with longitudinal slits for pollen shedding. Here the ovary is rudimentary. In the Female flowers, Staminodes (sterile stamens) are present and there is a single Pistil (a unit of the Gynoecium, the female element of the flower, composed of the Ovary, Style and Stigma). The 2-locular Ovary is superior or half-inferior, the Style is short and terminates in a capitate (formed like a head) Stigma. Flowers are Pollinated by insects. (Oct-Dec).
The oval or spherical Fruit is a pinkish-red Drupe (a fleshy, 1-seeded indehiscent fruit with the seed enclosed in a stony endocarp; stone fruit e.g. peach). It is up to 1,2cm wide and is situated on a stout stalk. The fruit is initially a mottled green that turns red when ripe. The outer covering is easily removable with the fingers. Below this is the putamen (endocarp; the shell of a nut; the stone of a drupe fruit). This is clasped at the base by orange or red pseudo-aril. An aril is an appendage or outer covering of a seed and may appear as a pulpy covering. It develops from a stalk, the funiculus, connecting an ovule or a seed with the placenta. Within the putamen is a single fertile black seed in one locule and 1 abortive ovule in the other locule. (Nov-Mar).
Distribution & Ecology
These Trees are located from East London in the Eastern Cape – especially on north facing slopes, Kwazulu-Natal, and Limpopo and in kloofs (steep-sided, wooded ravines or valleys) in Mpumalanga. It also grows in Swaziland and extreme south of Mozambique. These plants grow in dry forests and valleys – in bushveld as well as near rocky outcrops. They also occur as part of coastal forests. Elephants eat the Roots and Bark. Monkeys and birds eat the Fruit.
Household instruments and stools are made from the white, soft Wood. Local people eat the soft heartwood in times of need. Living fences can be grown from cuttings. It makes a good bonsai tree.
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.