General Info

Tree may reach 3m high. The trifoliate Leaves are small. Individual unisexual, Flowers are tiny, actinomorphic, 5-merous and in hanging panicles. Fruit: a drupe with a reniform Seed.

Description

Tree

Searsia undulate, Rhus celastroides, Rhus excise, Rhus undulate.

RSA Tree No. 389.

Common names: Kuni-bush (applied to those with obovate leaflets with wavy margins and a waxy surface).

Family:  Anacardiaceae (Mango family), which has about 83 genera and 850+ species – including Cashew). Resin canals are present and woolly stellate hairs cover all young parts. Leaves lack stipules. They are deciduous or evergreen and usually alternate. Leaves are simple, trifoliate or digitally compound and imparipinnate. When present, leaflets are usually opposite. Crushed leaves may smell of turpentine. Trees are monoecious or dioecious with occasional bisexual Flowers. Flowers are small, usually regular and unisexual. The Calyx has 4-7 sepals and there are 4-7 Petals. The number of Stamens is the same as, or twice the number of petals and the Anthers are versatile. The superior Ovary has up to 4 locules, each with a single ovule. The 1-5 Styles are free or connate and separated at the base. Fruit is usually an indehiscent fleshy drupe with a single Seed. The southern Africa genera include Harpephyllum, Lannea, Loxostylis, Ozoroa, Sclerocarya and Searsia.

Name derivation: Searsia: Named after Paul Sears an American ecologist (December 17, 1891 – April 30, 1990). undulata – wavy margin. There are about 75 species of Searsia in southern Africa. A most impressive specimen of Searsia undulata can be seen at the Pretoria NBG.

Conservation Status: LC. (least Concern). 2009.

This Tree is up to 3m high. However, it is usually a shrub. The Bark is grey-brown and smooth and may be glandular. In older plants, the underlying reddish bark can be seen (photo 245). The plant is much branched. The Branches are dark brown and divaricate (spreading very far apart; extremely divergent; to branch at a wide angle). Branchlets are angular and they may be ribbed.

Leaves

The relatively small – up to 5 x 2cm Leaves on this evergreen tree are trifoliate (compound leaf with 3 leaflets). Leaflets are olive green and sticky to shiny with pellucid (clear, almost transparent in transmitted light) veins. They are membranous and aromatic when crushed. Leaves are oblanceolate (the reverse of lanceolate, as leaf broader at the apical third than at the middle and tapering towards the base) to obovate. The Petiole (stalk of leaf) is up to 2,5cm long and may be winged – clearer to see in the upper half. The central leaflet is the largest. Petiolules (stalk of leaflets) are absent. The Margin is wavy and entire or slightly toothed. The Base is attenuate (showing a long, gradual taper). The Apex is retuse (having a rounded or obtuse apex with a central shallow notch) or blunt or even sharp tipped. The blade has lateral veins that are parallel and visible on both surfaces.

Flowers

The minute greenish-yellow Flowers occur in hanging Panicles (indeterminate, branched inflorescence with stalked flowers). Individual flowers are actinomorphic (regular, symmetrical. Perianth: calyx and corolla are divisible into 3 or more identical sectors or mirror images). The male panicle is up to 10cm long. Male flowers have 5 Stamens. Here the free Filaments each end with an Anther with 2 Thecae (pollen sacs), which dehisce longitudinally. Male flowers lack an Ovary but a rudimentary pistil is present. Flowers are either in axillary or terminal positions. The Female or hermaphrodite panicles are shorter and less branched. Here each flower has a single Pistil (a unit of the Gynoecium, the female element of the flower, composed of the Ovary, Style and Stigma). 3 free Styles are present and each small Stigma is capitate (formed like a head). (Jan-May).

Fruit

The Fruit is a small, shiny, dull yellow to cream, thinly fleshy, hairless and an almost spherical Drupe (a fleshy, 1-seeded indehiscent fruit with the seed enclosed in a stony endocarp; stone fruit e.g. peach) which is up to 5,5 x 6,5mm. Seeds are reniform (kidney shaped) and lack endosperm (the starch and oil-containing tissue of many seeds; often referred to as the albumen).

Distribution & Ecology

These plants are Located in the Northern and Western Cape in dry country. The larva of the Silver Arrowhead (Phasis thero) butterfly feeds on the leaves and been found on the stems. The red-flowered partial parasite: Lighted Candles Mistletoe (Moquiniella rubra) occurs regularly on this plant.

Ethnobotany

This plant is used in traditional medicine.

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.

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

 

http://redlist.sanbi.org/species.php?species=5522-153

kyffhauser.co.za/Plants1/Searsia_undulata/Index.htm

https://www.wits.ac.za/media/migration/files/cs-38933-fix/migrated-pdf/pdfs-1/background%20to%20recommended%20english%20common%20names.pdf