270 R. Marloth, Ph.D., M.A.— The [Oct. 26, 



been changed by Prof. Engler to that of A. Marlothii. Amongst all 

 the South African species this is the only one which is unarmed. 



There are eight species of acacias growing to the size of consider- 

 ;able trees. 



I mentioned already the common Karroo-thorn {A. horrida TVilld.), 

 which abounds on the banks of rivers and water-courses in the coun- 

 tries east and north of us. It forms beautiful groves ; for instance, on 

 the banks of the Orange River, as may be seen from the charming 

 painting in Burchell's book above quoted. It does not, however, 

 always grow in such clumj:.s of slender stems. In the Eastern 

 Province, for instance near King William's Town, numerous isolated 

 trees stand on the slopes of the hills, reaching a height of 20 to 30 

 feet, and in Damaraland I saw trees 50 feet high. Its name horrida 

 has not been given without sufficient reason. The geminose spines, 

 as white as ivory and often as long as a finger, are as sharp and 

 pointed as a needle. Hence the branches of this acacia are very 

 welcome to the traveller when he is obliged to erect a kiaal for his 

 cattle, for even the roaring of a lion will not terrify his oxen to such 

 an extent that they would break through a fence of this kind. 



Another species, A. hebeclada Dc, is also of a very variable size. 

 Generally occurring only as a shrub, a few feet or yards high, it forms 

 on more favourable places considerable trees with a trunk as thick 

 as a man's body. This species, I think, boasts of more formidable 

 weapons than any other one, for its strong and sharp hooks are often 

 an inch long, and, being covered with a fine tomentum, not only 

 lacerate the flesh, but produce a very painful itching, which lasts 

 long after the wound has been inflicted. 



Straight spines and recurved hooks are combined on another 

 ;acacia, w^hich Burchell named appropriately A. heteracaniha, although 

 there are several other species armed in the same manner. There is, 

 however, no specimen known which with safety can be referred to 

 this name. I thought first that a species pretty common in Griqua- 

 land West should be considered to be Burchell's A, heteracmitha, but 

 the shape of its legumes differs so widely from B.'s description, that it 

 has been necessary to give it another name {A. spirocarpoides Engler^. 

 It is only 15 to 20 feet high, but another species, similar in its external 

 appearance and differing also by its legumes (^A. Maras Eiigler), 

 grows to a lofty tree of 40 to 50 feet, adorning the valleys of Damara- 

 land. These three species are, as I suppose, the Haak en steek of the 

 Dutch colonist, for the long spines prick the unfortunate victim which 

 4;he hooks prevent from escaping. 



