BENTHAM ON MIMOSE.E. 325 



pules; aculei caulini, or aculei petiolares, are prickles pro- 

 duced by the cuticle of the stem, or of the petiole; it has 

 therefore appeared to me necessary to suppress altogether 

 the expression aculei stipulares, applied, not to aculei grow- 

 ing on the stipules, but to the not uncommon aculei arising 

 from the stem in pairs, one immediately under each stipule, 

 and which have so often been mistaken for spin<B stipulares. 

 It is more difficult to fix on an appropriate nomenclature 

 for the various appendages to the petioles of Jfimosea', which, 

 on some occasion or another, have received the name of 

 glands, although very diiferent from each other in their 

 origin and importance, as will be seen from the following 

 enumeration : — 



1. The base of the petiole, whether common or partial, as 

 well as the petiolule of the leaflet, is often thickened, and of 

 a glandular or somewhat cartilagineous consistence, some- 

 thing analogous to what the French term a bourrelet. This 

 portion of the stalk is by some called a gland; but it appears 

 to me that the name is thus misapplied; nor do I see any 

 occasion forgiving a special name to what is neither an organ 

 of itself, nor yet a definite portion of another organ. 



2. I have, with most botanists, considered as true petiolar 

 glands, those which, when they exist, are always to be found 

 on the upper surface of the common or partial petioles. 

 They are usually sessile, oblong, ovate, or orbicular, depressed, 

 concave or convex, and single, either below the lowest pair of 

 pinnse alone, or one between, or a little below, one two or 

 more pair of pinnae or leaflets, beginning with the extreme 

 pair. When pinnae are not exactly opposite, it sometimes, 

 but rarely, happens, that there are two of these glands 

 together, one under each pinna. 



3. A small point terminates the petioles, whether common 

 or partial, in all or nearly all Mimosece. It is usually seti- 

 form, thoun-h sometimes short and thick, and occasionally 

 almost foliaceous, sometimes apparently continuous with the 

 petioles, at others falling readily off. This point has by 

 some been termed a gland ; but it would appear, erroneously 



