192 BUDS AND STIPULES 



members of the family Rubiacece. He does not, how- 

 ever, regard them as stipules, but as ' sac-like 

 outgrowths of the blade.' They lie at the base of the 

 leaf, near the middle nerve. 



In Korthalsia also, a Malayan Palm, the base of the 

 petiole is swollen into a sort of ocrea, in which a species 

 of ant makes its home. 



Spiny stipules also occur in Porlieria, an American 

 genus, a member of the family Zygoj)ltyllacea^ in Paliiirva, 

 one of the Rhamnece, &c. 



Nectariferous Stipules 



Kerner was, so far as I am aware, the first who 

 called special attention to the importance of extrafloral 

 nectaries in the economy of plants. He, however, 

 suggested that their function was to keep ants away 

 from the flowers. The real object seems, rather, to be 

 to attract ants, which, as already mentioned, protect 

 the plant from various enemies from caterpillars, 

 leaf-cutting ants, &c. Every fruit-grower in Java 

 knows how ants protect the plant from fruit-eating 

 bats (Pteropus). Nectaries are often situated on the 

 calyx, and the presence of ants protects the flowers 

 from being bored through at the base by bees. Some 

 species of Smilax also have winged petioles, in which 

 ants make small nests. 



As an illustration of glandular stipules may be 



