816 
Acacia horrida. (L.) Willd. (Mimosaceae . ) 39355. Seeds 
of the doorn-boom or thorn-tree of South Africa, presented by 
Mr. J. Burtt-Davy, Agricultural Supply Association. "A 
glabrous -flat-topped tree, usually spreading more than its 
height. The most widely distributed of all South African 
trees, extending from Capetown through the Karroo to 
Damaraland, Orange River Colony, Transvaal, Natal, and 
Delagoa Bay. Its range is however curiously affected in 
places, being absent, possibly through frost, in several 
large flat alluvial localities where single trees have 
grown to perfection. It ascends to about 4000 feet alti- 
tude from the eastern coast and considerably further from 
the western, but is absent from the higher parts of the 
Drakenburg, and seldom mixes with Proteaceae, thus indica- 
ting that soil as well as climate controls its distribu- 
tion. Occasionally it forms a fine spreading tree 30-40 
feet in height, and with stem 2 feet in diameter, much 
more frequently it is a small umbrella-shaped tree of 10 
to 15 feet in height with a clear bole only to 6 or 8 
feet, and the constant regrowth dots or covers the veld 
with all smaller sizes in suitable localities where it is 
not kept down. Although usually evergreen, yet in dry 
cold carrold localities it is often leafless for a con- 
siderable part of the year, and in some localities it is 
continuously leafless for years in succession, and is then 
enormously spiny and colors the veld whi^te instead of 
green. In most places its use is principally for fuel, 
for which purpose there is no better wood; but as this 
does not, except near the towns, use up all that grows, 
its increase in remote localities is a difficult matter to 
check. Fire burns the grass under mature thorn- trees 
without doing them much damage, and as the seeds germinate 
most readily after being soaked in boiling water or half 
roasted, those grass fires aid rather than retard re- 
growth. Chopping off trees at the ground only induces 
an abundant coppice growth, but it is found that by chop- 
ping them off two feet above ground during summer, the 
coppice growth is more easily controlled, and the stump 
often dies. Native locations usually become free of thorn- 
tree eventually, partly through the unrestricted native 
demand for fuel, kraalwood, etc., and partly through the 
browsing of goats, which of all artificial methods is the 
surest means of keeping the tree down. A small brown 
scale-insect, however, (Prosopophora prosopidis, var. mimosae) 
is found to kill the trees wholesale on the occasions of 
its visits in the Bedford district. During very dry win- 
ters it is not an uncommon practice to fell a few leafy 
thorn-trees daily as a green bite for stock; during summer 
the shade of the spreading tree is sought after by cattle 
and sheep; young plants are always browsed, and when ob- 
