248 THE JOURNAL OF BOTANY 
be made of them. In some species there is a tendency 
elimination of the prickles, especially on the flowering-shoots, 
and specific characters have been founded upon this. Weh 
found it too variable a feature to be of more than secondary 
importance. 
Leaflets —The number of leaflets in many groups is of little 
nin 
nine is the prevailing number. Their spacing on the petioles, and 
that of the whole leaves on the branches, varies a good deal, so as 
to give many of the species a characteristic appearance of laxity 
or denseness. 
ones, nor is a species which usually has them lanceolate likely to 
be found with orbicular ones. The terminal leaflet is the one 
their petiolules. 
eir serration has always been regarded as a primary char- 
acter. It naturally falls into two categories, “ simple” 
