154 GENERAL BOTANY 



generally at the tips of teeth or lobes. This is termed 

 palmate venation. These main veins are generally 

 branched again pinnately, so that the term palmate 

 refers only to the main veins. 



In NELUMBIUM (Sacred-lotus) and TROP^OLUM 

 (Garden-nasturtium) the petiole meets the blade not 

 at the edge but inside it, and the veins radiate out in 

 all directions. This is the most perfect form of palmate 

 venation, and a leaf of this kind (i.e. with the petiole 

 attached inside the margin of the blade) is termed 

 peltate. The venation of ZIZYPHUS is very charac- 

 teristic, veins enter the blade palmately, the two 

 lateral veins branch pinnately, with strong secondary 

 veins towards the outside, much weaker ones on the 

 inside. The middle vein also branches pinnately, but 

 the side veins are here rather weak. 



Leaves with parallel venation are always entire, 

 those with palmate venation are either roundish as 

 in NELUMBIUM and TROP^OLUM or lobed, the side 

 veins ending in the lobes, as in ordinary Cotton plant, 

 STERCULIA, and many others. 



3. In describing leaves, it is usual to begin with 

 its position and nature (simple or compound) and 

 the presence or absence of a stalk ; then to give the 

 general shape of the blade (or perhaps of the whole 

 leaf if it is compound) using the terms given in 

 section 2 simply or in combination as may be required ; 

 the shape of the base or apex, if it is distinctive 

 enough, follows ; then the nature of the edge ; of the 

 surface and of the texture; and finally the venation, 

 if characteristic. Thus the leaves of PLUMERIA ALBA 

 (fig. 27) ' are alternate, simple, shortly petioled, oblong, 



