ON THE SUBSIDIARY USES OF STIPULES 191 



can be relied on, many of the specimens thus affected 

 are from the richest moist forest regions of tropical 

 America. They never appear to affect the whole of the 

 stipules of any one bush, varying in degree of develop- 

 ment in the several pairs of stipules of the same branch, 

 but affecting special forms and tinges of colour, from an 

 ivory-white to a livid purple, for each species.' 



The Common Bulls-horn (Acacia cornigera), described 

 by Belt (21), bears hollow thorns, while each leaflet pro- 

 duces honey in a crater-formed gland at the base, as 

 well as a small sweet, pear-shaped body at the tip. In 

 consequence it is inhabited by myriads of a small ant, 

 which nests in the hollow thorns, and thus finds meat, 

 drink, and lodging all provided for it. These ants are 

 continually roaming over the plant, and constitute a 

 most efficient bodyguard, not only driving off the leaf- 

 eating ants, but, in Belt's opinion, rendering the leaves 

 less liable to be eaten by herbivorous mammals. 



Bower (2 2) describes another interesting case of a 

 myrmecophilous plant Humloldtia laurifolia. The 

 stipules consist of two parts: a lower, sagittate part, 

 with four to six glands on its upper face, and an 

 ovate-lanceolate part, with one or more glands, on the 

 lower surface ; they originate from two outgrowths at 

 the base of the leaf-stalk below the leaflets. 



K. Schumann (23) figures the bladders, inhabited 

 by ants, at the base of the leaves of Duroia saccifera 

 and Remijia physophora, both tropical South American 



