THE LEAF. 



35 



divisions are called lobes. If the incisions extend more 

 than hplf-way from the margin to the midrib, the leaf is 



said to be cleft (Fig. 72) ; the number of segments are 

 indicated by- the terms bifid (two-cleft), trifid (three- 

 cleft), tnultiiid (many-cleft), etc. If the divisions extend 

 almost to the midrib, the leaf is said to be parted ; if 

 they extend quite to the midrib, the leaf is divided ; and 

 thus a simple leaf, or one with lamina in a single piece, is 

 converted into a compound leaf, that is, one with the 

 blade divided into several parts (Fig. 73). Each of the 

 latter is called a leaflet (Fig. 

 73, Ift), and the stem or mid- 

 rib, which supports the leaf- 

 lets, is called the rachis (Fig. 

 73, rach). 



41. Corresponding with the 

 pinnate and palmate type of 

 venation, there are pinnately 

 and palmately compound 



Figs. 07-71. Margin of leaves : 67. Serrate ; 68. Dentate ; 69. Crenatc ; 70. Un- 

 dulate; 71. Incised, Fig. 72. A Cleft leaf. Fig. 73. A divided, j.?. compound, leaf 

 of the rose : l/t, leaflets ; rach, rachis ; itif, stipules. 



