EXTRAORDINARY WILD YAM 



Even the Kameeldom, Camelthorn Acacia, or the Wait-a- 

 bit in South Africa cannot defend itself. 



The Wait-a bit (Wacht cen hcetje) is so called from the 

 ingenious nature of its spines. There are two together, of 

 which one is straight and the other curved round like a hook. 

 Both are very sharp and strong, so that an incautious traveller 

 is sure to injure himself and his clothes. The straight one 

 runs into his tender flesh, whilst the curved one fixes itself in 

 his clothes. 



It is by thorns, spines, and prickles that plants often 

 protect themselves against the attacks of grazing animals. 

 But it must be remembered that these are by no means the 

 only safeguard. Plants produce poisonous, bitter, or strong- 

 smelling substances which keep off their enemies, and these 

 indeed often afford a more efficient protection (see Chap. iii.). 

 These thorns, etc., can be produced in the most unexpected 

 places. There is one rule, however, namely that they are 

 invariably found in the exact spot where they can be most 

 useful. 



Thus there are certain palms which possess green, juicy 

 leaves, much relished by snails. These are protected by a 

 sort of spine entanglement formed upon certain roots, 

 which grow at the base of the leaves. Nor is this the only 

 case in which spines are found on roots. There are certain 

 South African bulbs {Moroea) which are protected from the 

 wild pigs by a dense mass of spiny roots.^ On my march to 

 Uganda from Mombasa, I was very much astonished to see 

 an extraordinary Wild Yam. It had a huge underground 

 tuberous part full of starchy matter, but it was quite im- 

 possible for any marauding wild boar to get at it, for it was 

 entirely enclosed in a sort of arbour of long, arching roots 



1 Scott, Annals of Botany ^ vol. 11, p. 327. 

 i8o 



