76 



PLANT BIOLOGY 



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FIG. 97. DlGITATELY PARTED LEAVES 

 OF BEGONIA. 



parted, if the sinuses 

 reach two thirds or more 

 to the midrib (Fig. 97); 



divided, if sinuses 

 reach nearly or quite to 

 the midrib. 



The parts are called 

 lobes, divisions, or seg- 

 ments, rather than leaf- 

 lets. The leaf may be 

 pinnately or digitately 

 A pinnately parted or 



lobed, parted, cleft, or divided. 



cleft leaf is sometimes said to be pinnatifid. 



Leaves may have 

 one or all of three 

 parts blade, or 

 expanded part ; pe- 

 tiole, or stalk ; stip- 

 ules, or 

 appendages 

 at the base of the 

 petiole. A leaf that 

 has all three of these 

 parts is said to be 

 complete (Figs. 91, 

 1 06). The stipules 

 are often green and 

 leaflike and per- 

 form the function 

 of foliage, as in 

 the pea and Japanese quince (the latter common in yards). 



Leaves and leaflets that have no stalks are said to be 

 sessile (Figs. 98, 103), i.e. sitting. Find several examples. 



FIG. 98. OBLONG- I OVATE SESSILE LEAVES OF 

 TEA. 



