FORM OF LEAVES 



91 



123. Compound or branched leaf of brake 

 (which is a fern I. 



191. FORM. Leaves are simple or unbranched (Fig. 



124), and compound or branched (Fig. 125). The 



method of compounding or branching follows the style 



of veining. The veining, or venation, is of two general 



a kinds: in most plants 



the main veins di- 

 verge, and there is a 



^^J^^Mr5^r^^*^^Sft?R conspicuous network 



of smaller veins: such 

 leaves are netted- 

 veined. In other 

 plants the main veins 

 are parallel, or nearly 

 so, and there is no 

 conspicuous network : 

 t h ese are parallel- 

 veined leaves (Fig. 136). Tin- venation of netted- veined 

 leaves is pinnate or feather-like, when the veins arise from 

 the side of a continuous midrib (Fig. 1'24) ; palmate or 

 digitate (hand -like), when the veins arise from the apex 

 of the midrib (Fig. 126). If the leaf were divided be- 

 tween the main veins, it would 

 be pinnately or digitately com- 

 pound. \ ; 2 : 1 1 



1D2. Il is customary to speak m 

 of a leaf as compound only when 

 the parts or branches are com- 

 plete^ separate blades, as when V 1 R/ 

 the division extends to the midrib '' 



(bigs. L25, 127, L28). The parts 126. Digitate-veined peltate leaf 

 ii i , , of nasturtium. 



or branches are known as leaf- 

 lets. Sometimes the leaflets themselves arc compound, and 

 the whole leaf is then said to be bi-compound or twia 

 compound (Fig. 125). Some leaves are three -compound, 

 four - compound, or five - compound. Decompound Is a 



