General Info

This Tree may reach 6m and spines may be present.  Leaves may be trifoliate or simple.  The small unisexual Flowers are bell-shaped and yellowish.  Fruit is a fleshy berry.  Seeds have a yellow pseudo aril.

Description

Commiphora viminea, Commiphora merkeri.

RSA Tree No. 279.

Common names: Zebra Tree, Zebra-bark Corkwood, Zebra-barked Corkwood.

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.  viminea – with long flexible shoots.

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

Tree

The upright single Trunk makes this Tree easy to identify.  The tree may reach 6m in height.  The mature tree has a grey or yellowish Bark which is patterned horizontally with large, bulging, rough black strips of Lenticels (usually raised corky oval or elongated areas on the plant that allows the uncontrolled interchange of gases with the environment) resembling zebra markings – hence the common name.  Between these rough strips, the bark is pale yellow-green and tends to flake in paper-like pieces.  The purplish Branches are smooth and may contain spines together with leaves on dwarf shoots.  Resin ducts are present in the bark and help to make the bark aromatic.

Leaves

This deciduous tree may be leafless from June to September.  The Leaves appear and develop on dwarf lateral branches.  Leaves are usually simple but may be tri-foliate (compound leaves with 3 leaflets). They are up to 4,5 x 2,5cm.  The leaflets are very small on trifoliate leaves.  The leaf is narrowly ovate, obovate or elliptic.  Leaves are bluish green above and have a distinctive greyish bloom.  The Apex is often rounded.  It may taper slightly.  The Base tapers and has long glandular hairs.  The leaf Margin is scalloped – especially towards the apex.  The Petiole (leaf stalk) is very short or absent.

Flowers

The small unisexual, yellowish green Flowers appear before or with the new leaves on spur branches.  Flowers are tiny, about 3mm long, bell shaped and yellowish.  They develop in small flowerheads in leaf axils.  Flowers are 4-merous, actinomorphic (having symmetrically arranged perianth parts of similar size or shape that are divisible into 3 or more equal halves) and located in small flower heads in leaf axils.  The Calyx is hairless and has 4 Sepals that are joined at the base.  The Corolla has 4 Petals which alternate with the sepals and are tubular at the base.  A cylindrical Disc (a more or less fleshy or elevated development of the receptacle) is present.  The Male flowers are usually larger than the female flowers.  Here the 8 Stamens are in 2 whorls of 4 and 4, with the outer whorl opposite the petals. Those from the outer whorl or on top of the disc.  The Anthers are introrse (turned or faced inward or toward the axis) and have longitudinal slits.  Here the ovary is rudimentary.  The Female flowers have staminodes present.  There is a single pistil (a unit of the Gynoecium, the female element of the flower, composed of the Ovary, Style and Stigma) and the superior Ovary has 2 locules.  (Nov-Jan).

Fruit

The fleshy Fruit is an almost spherical and a slightly pointed Drupe (or stone fruit is a fleshy, indehiscent fruit with the seed enclosed in a stony endocarp).  It is about 1,3cm long.  These hairless fruits are reddish brown when ripe and split to reveal the yellow 3-4 lobed arilode (false-aril – a structure in certain seeds that resembles an aril but is developed from the micropyle of the ovule as opposed to the stalk) which almost surrounds the stone, which covers the Seed. (Nov-Mar).

Distribution & Ecology

These Trees are found in Limpopo – north of the Soutpansberg e.g. Chipisi hot mineral springs and Mapungubwe National Park.  They grow in Botswana, Zimbabwe and into tropical Africa.  Trees occur at low altitude in dry, hot areas associated with Colophospermum mopane.

Ethnobotany

The Wood is of little use.  The trees can be grown from Seed and are quick growing.  The Stem has been reported to have some anti-cancer properties.

References

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.

 

http://redlist.sanbi.org/species.php?species=1511-41

http://sagr.co.za/forum/viewtopic.php?p=230593

http://www.zimbabweflora.co.zw/speciesdata/species.php?species_id=133410

https://www.ncbi.nlm.nih.gov/pubmed/18640253

http://www.nbri.org.na/sites/default/files/treeatlas/pdf/TAP_Commiphora%20discolor.pdf

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