96 



LEAVES AND FOLIAGE 



when the veins arise from the side of a continuous midrib 

 (Fig. 138); palmate or digitate (hand-like), when the veins 



arise from the apex of 

 the petiole (Fig. 140). 

 If the leaf were divided 

 between the main veins, 

 it would be pinnately 

 or digitately compound. 

 204. It is customary 

 to speak of a leaf as 

 compound only when 

 the parts or branches 



139. C^poundor branched leaf of brake are comp letely separate 



blades, as when the 



division extends to the midrib (Figs. 139, 141, 142). The parts 

 or branches are known as leaflets. Sometimes the leaflets 

 themselves are compound, and the 

 whole leaf is then said to be bi-com- 

 pound or twice-compound (Fig. 139). 

 Some leaves are three-compound, four- 

 compound, or five-compound. Decom- 

 pound is a general term to express any 

 degree of compounding beyond twice- 

 compound. 



205. Leaves that are not divided 14 - Digitate-veined peltate 



,r -j M ! , i leaf of nasturtium. 



to the midrib are said to be: 



lobed, openings or sinuses not 



more than half the depth of 



the blade (Fig. 143). 

 cleft, sinuses deeper than the 



middle. 

 parted, sinuses two -thirds or 



more to the midrib (Fig. 144). 

 divided, sinuses nearly or quite 



141. Pinnately compound leaf of ash. to the midrib. 



