190 BUDS AND STIPULES 



' occupent exactement la meme place que les stipules 

 epines du Eobinia Pseudacacia. II n'est, des lors, pas 

 etonnant que Ton ait quelquefois considere ces epines 

 comme des stipules.' This, however, he disputes, because 

 they are ' purement parenchymateuse,' a reason which, 

 however, is by no means conclusive. 



Azima, belonging to the exotic family Sa&vad&raowe, 

 is another genus which has spines at the base of 

 the leaves. 



Du Petit Thouars regarded the spines of the Orange 

 as stipules, but they are now regarded, no doubt with 

 reason, as aborted branches (I9,i). Stipules in the form 

 of spines also occur in Ribes oxyacantlwides, some species 

 of Bauhinia (B. grandiflora), Paliurus, &c. These spines 

 serve to protect the plant from herbivorous quadrupeds. 



Spiny stipules in some cases serve to protect the plant 

 in another and very curious manner. ' In the Mimo- 

 secB,' says Bentham (20), ' spinescent stipules are met 

 with in various groups, especially in the Acacue Giimmi- 

 ferce and Pulchellce, and a few Phyllodinece and others, 

 and, as far as has been observed, are always independent 

 of physical conditions. In the Acacice Oummiferce, 

 whether from tropical America, Africa, or Asia, they 

 offer the curious phenomenon of an extraordinary 

 development of some of the pairs, or sometimes of nearly 

 all of them, assuming the aspect of horns of cattle. 

 Such horn-like enlargements are most general in dry, 

 hot regions ; but, as far as the information of collectors 



