This shrub or small tree, with its lobed discolorous leaves, large
sharp prickles and large poisonous yellow fruit, has long been used
as a hedge plant.
This much-branched shrub or small tree is 1-5 m high, usually heavily
armed with large, sharp, brown, straight to recurved, broad-based
and laterally compressed prickles up to 15 mm long. Young branches
are covered with a grey or pale brown tomentum, becoming glabrous
and dark brown with age. Leaves are shortly petiolate, ovate, up
to 150 × 130 mm, usually deeply 5-7-lobed, with the upper
surface green glabrescent, the lower surface thickly stellately
whitish tomentose, more or less prickly on the midrib on both surfaces.
The inflorescence is a few to 10-flowered racemose cyme with only
the proximal flowers female-fertile. The calyx is enlarged and prickly
in fruit. The corolla is white to pale violet, rotate-stellate,
about 20 mm in diameter. The fruit is a smooth, globose berry, often
with a warty surface, up to 60 mm in diameter, green ripening to
yellow. Seeds 4 × 3 mm in size. Chromosome number: 2n = 24.
The lobed discolorous leaves, the mostly recurved prickles and
the large yellow fruit make this plant unique among the African
species of Solanum. It could perhaps be confused with S.
lichtensteinii (= S. incanum in the broad sense ), but
that small shrub is unarmed or has small prickles.
The flowering time is from September to July, peaking in November
and March. The fruiting time is from April to January, peaking in
June and November.
Distribution and habitat
S. aculeastrum subsp. aculeastrum occurs from tropical
Africa down to South Africa. There are two other subspecies that
are restricted to East Africa. In southern Africa this taxon is
found in Limpopo, Mpumalanga, KwaZulu-Natal, Western and Eastern
Cape and also in Swaziland.
S. aculeastrum subsp. aculeastrum occurs naturally
in grassland, woodland and in forest margins, but also in disturbed
places. In southern Africa it prefers a high rainfall of more than
700 mm per year and it is found from 275-1 780 m altitude. It has
been recorded from gentle to steep slopes and on all aspects, on
various soil types e.g. sandy soils, reddish brown clay-loam and
brown sandy loam.
Acocks (1988) regards this species as an undesirable plant which
should be reduced in number by appropriate veld management. It is
listed as a component of the North-eastern Mountain Sourveld.
Derivation of the name
As discussed under S. giganteum, Jaeger
(1985) explains that the genus name Solanum is possibly connected
to the Latin noun solamen, meaning a relief or comfort, assumed
from the palliative effects of the nightshades. The species name
aculeastrum refers to the sharp-pointed prickles on most
parts of this plant.
The Solanaceae is an economically important family of about 2 600
species of plants, with its chief centre of diversity in Central
and South America. This family contains many poisonous, medicinal
and edible plants, and also several horticultural favourites as
well as many weeds. Solanum is a large, cosmopolitan genus
of perhaps as many as 1 500 species; about 50 of these species are
found in southern Africa and about 30 of them are indigenous.
S. aculeastrum belongs to the section Melongena of
the subgenus Leptostemonum. Species of this section are found
in Africa and Asia; one of which is the cultivated S. melongena
(egg-fruit, aubergine, brinjal) which was probably domesticated
in China, and which today is an important vegetable, particularly
in the Mediterranean and Asia, belongs here. About seven species
of this section occur naturally in Africa and they all have white
to violet flowers and yellow, fleshy fruits. S. aculeastrum
appears on the official Tree List of South Africa (no. 669.3) and
of Zimbabwe (no. 1013).
Uses and cultural aspects
In rural areas the goat bitter-apple is in common use as a hedge
or as living fencing material for retaining livestock. It is sometimes
used as a windbreak. It is well suited for these purposes because
of its fast growth, its eventual size and in particular its large,
hooked prickles. As a result it is often found growing in thickets
close to human dwellings. The fruit is sometimes used as a soap
substitute; apparently it has a high saponin content.
According to Hutchings et al. (1996), the extremely bitter fruit
of S. aculeastrum is used medicinally (fresh, boiled or burnt)
in various ways for humans as well as domestic animals. The fruits,
both mature and immature, contain the poisonous alkaloid solanine.
Growing Solanum aculeastrum
This plant could be an attractive garden subject, but unfortunately
no information can be found. It is clear that it can be grown fairly
easily in high rainfall areas and that it can tolerate some frost.
It can probably be propagated by truncheons and from seed.
- Acocks, J.P.H. 1988. Veld types of South Africa, edn 3. Memoirs
of the Botanical Survey of South Africa No. 57. Botanical
Research Institute, Pretoria.
- Dold, A.P. & Cocks, M.L. 1999. Preliminary list of Xhosa
plant names from Eastern Cape, South Africa. Bothalia 29: 267-292.
- Hutchings, A., Scott, A.H., Lewis, G. & Cunningham, A.B.
1996. Zulu medicinal plants, an inventory. University of
Natal Press, Pietermaritzburg.
- Jaeger, P.-M.L. 1985. Systematic studies in the genus Solanum
in Africa: 1-540. Ph.D. thesis, University of Birmingham.
- Van Wyk, B. & Van Wyk, P. 1997. Field guide to trees
of southern Africa. Struik, Cape Town.
- Von Breitenbach, F. 1981. Standard names of trees in southern
Africa, Part II: Venda tree names. Journal of Dendrology
1,3 & 4: 84-94.
- Von Breitenbach, F. 1991. Standard names of trees in southern
Africa, Part VII: Setswana tree names. Journal of Dendrology
- Von Breitenbach, J., De Winter, B., Poynton, R., Van den Berg,
E., Van Wyk, B. & Van Wyk, E. 2001. Pocket list of southern
African indigenous trees: including selected shrubs and woody
climbers, 1st abridged impression of edn 4. Briza Publications
& Dendrological Foundation, Pretoria.
- Watt, J.M. & Breyer-Brandwijk, M.G. 1962. Medicinal and
poisonous plants of southern and eastern Africa, edn 2. Livingstone,
Edinburgh & London.
National Herbarium, Pretoria