Volume I 
NOVEMBER, 1915 
No. 4 
EXTRA-TROPICAL SOUTH AFRICAN ACACIAE 
By RUTH GLOVER 
The genus Acacia consists of about 450 species and is confined to ti’opical 
and subtropical regions. By far the greatest number of species occurs in 
Australia. According to Thonner {Die Blutenpflanzen Africas), there are 
80 species in Africa, of which 24 occur in extra-tropical South Africa. All 
these are to be found in the Kalahari Region as understood by H. Bolus 
(. Science in South Africa, 1905), and the great majority are recorded 
from the Transvaal. The most widely spread species, A. Karroo, Hayne 
{A. horrida, Willd., the common karroo thorn) occurs as far south as Worcester 
in the west and Uitenhage Division in the east. This species has been found 
on the slopes of Lion’s Mountain in the Cape Peninsula, but Bolus and 
Wolley Dod ( List of Flowering Plants and Ferns of Gape Peninsula) regard 
it as “ an outlier from the Karroo and doubtfully native.” 
Two species, A. haematoxylon and A. gi raff he (Ivameeldoorn) seem to be 
confined to the dry sandy plains of Bechuanaland. Several species including 
A. albida, A. pallens and A. lasiopetala are essentially tropical ones which 
have extended southwards. 
In habit, most are erect trees or shrubs ; two species, which extend from 
Natal along the coast-line into Mozambique (A. pennata, Willd., and A. Kraus- 
siana, Meisn.) are scrambling suffrutices. 
In this attempt to make a key for the South African species of Acacia, 
the character of the spines, as a distinguishing mark for a species, has been 
disregarded, as the spines vary considerably on the same plant and often the 
flowering branches do not bear spines at all or they are not developed until 
after the flowering period. 
In A. caffra, Willd., true spines are never present, but prickles are usually 
developed in pairs below the foliaceous stipules. Prickles are usually piesent 
in A. eriadenia, Benth., and A. ataxacantha, DC., scattered ii regularly o\ci 
the branches and branchlets. Bentham {Monograph of the Mimoseae in 
11 
A. B. H. 
