160 



THE LEAVES. 



base of the blade or the midrib, the leaf is said to be parted (Fig. 

 262, 266) : if they reach the midrib or the base, so as to interrupt 



the parenchyma, the leaf is said to be divided (Fig. 263, 267) ; the 

 number oi partitions or divisions being designated, as before, by the 

 terms two-, three-, five-parted, or two-, three-, five-divided, &c. 



283. As the mode of division always coincides with the arrange- 

 ment of the primary veins, the lobes or incisions of feather-veined, 

 are differently arranged from those of radiated or pahnately veined 

 leaves : in the latter, the principal incisions are all directed to the 

 base of the leaf ; in the former, towards the midrib. These modi- 

 fications are accurately described by terms indicative of the vena- 

 tion, combined with those that express the degree of division. 

 Thus, a feather-viened (in the Latin form, a pinnately veined) leaf 

 is said to be pinnately cleft or pinnatifid (Fig. 261), when the 

 sinuses reach half-way to the midrib ; pinnately parted, when they 

 extend almost to the midrib (Fig. 262) ; and pinnately divided, 

 when they reach the midrib, dividing the parenchyma into separate 

 portions (Fig. 263). A few subordinate modifications are in- 

 dicated by special terms : thus, a pinnatifid or pinnately parted 

 leaf, with regular, very close and narrow divisions, like the teeth of 

 a comb, is said to be pectinate ; a feather-veined leaf, more or less 

 pinnatifid, but with the lobes decreasing in size towards the base, is 



FIG. 260-267. Pinnately and palmatel; lobed, cleft, parted, and diyided leaves. 



