58 THE PLANT SUCCESSION IN THE THORN VELD. 



tributed and to germinate on or around white-ants' nests. The 

 excavations of termites have also an important effect on the soil. 

 The nests are (frequently afterwards deserted and occasionally 

 the burrowings of the aard-vark or ant-bear. ( Orcytcropus 

 afcr) leads to considerable disturbance of the soil, and provides 

 further shade and shelter for young seedlings. As well as the 

 white ants, true ants are frequently present in great numbers, 

 and their effect on the soil in many places is most important 

 of all. An early stage, at the time when the overhanging acacia 

 is from 6 to 10 years old, is shown by the presence of such 

 plants as the following: The grasses Andropogon pertusits. 

 Sporobolus indiciis, Aristida angitstata; Lantana salvifolia. 

 Llppm asperifolia, Teucrinm capense, Acalypha sp., Lcpidium 

 sp., Ocimum sp., Lcucas martiiiicciisis, Vernonia sp., together 

 with any of the other associated ])lants of the veld, but other 

 invaders from the stream-bank and ravine flora soon make their 

 appearance. 



Species which follow the Pioneers (Fig. 2, Stages 5-8). 



Of the species which follow the pioneers (subsequent 

 species) at Bisley, the earliest arrivals are jasmines {Jasminum 

 multipartitum and /. gerrardi?). Their small fleshy drupes are 

 readil}^ eaten by birds. With them we get Raiidia nidis, which 

 has a small black berry. This species, according to Sim, in 

 some parts of the Fish River scrub forms a large part of the 

 Bush vegetation. Another early arrival is Ehretia hotteiitotica . 

 its fruit is an orange-red drupe, which is eaten by the natives. 

 Hippobromtis alata, with a black. Jiuljjy ifruit, is common at an 

 early stage ; it spreads by root-suckers, and young ])lants of it 

 appear all round the parent tree. Eiiclca iindidata (the guarri). 

 a species which is dominant over wide stretches of the Little 

 Karroo, sometimes appears under the thorn-trees among the 

 first, but another species of Euclea (E. lanceolata) is more 

 frequent. The Eucleas have berries, known as " guarri besjes," 

 which are eaten by the natives. The wild grapes, especially 

 Vifis cirrhosa and V. cuneifolia, are usually early arrivals. The 

 large tuberous swellings on their roots are characteristic. 

 Species of Solanum are also frequent. Cclastrns buxifolius, as 

 mentioned above, is sometimes itself a pioneer species ; at other 

 times it takes its place among the species which establish them- 

 selves in the shade of the thorn-trees. It has a capsule with 

 two or three arillate seeds. Zicyphus uincronata, the " wait-a- 

 bit '" thorn, which has numerous fleshy, dark-red, globose fruits, 

 is another widespread species of the Thorn V^eld. It is often 

 among the first invaders, but to establish itself it requires fairly 

 deep soil or open rocky situations- The cabbage tree, Cussonia 

 spicafa. the fleshy fruits of which are eaten by birds, and the 

 seeds of which do not seem to germinate readily unless thev 

 have been eaten, is another characteristic Thorn Veld species. 

 Species of Rhus are very numerous. They have one-seeded 



