64 



MORrUOI.OGY OF LEAVES AS FOLIAGE. [lESSON 9* 



Sugar-Maple and the Biittonwood (Fig. 50) haxc palmatcly Jii^C" 

 lobed leaves ; tlie Soft \f \niii-Mi\\)\(i jjcihnatelij Jive-parted leaves; and 

 so on. And in the other sort, the Post-Oak has pinnatdy seven- 

 to nine-Iohed leaves ; the Red-Oak commonly has pinnately seven- to 

 nine-cleft leaves, &;c., &;c. 



162. The divisions, lobes, &c, may themselves be entire (without 

 teeth or notches, loG), as in Fig. 118, 122, &c. ; or serrate (Fig. 

 124), or otherwise toothed or incised (Fig. 121 ) ; or else lobed, cleft, 

 parted, &c. : in the latter cases making tivice pinnatijid, twice pal- 

 viately or pinnately lobed, parted, or divided leaves, &;c. From these 

 illustrations, the student will perceive the plan by which the bota- 

 nist, in two or three words, may describe any one of the almost 

 endlessly diversified shapes of leaves, so as to convey a perfectly 

 clear and definite idea of it. 



103. Compound Leaves. These, as already stated (155), do not 

 differ in any absolute way from the divided form of simple leaves. 

 A compound leaf is one which has its blade in two or more entirely 

 separate parts, each usually with a sfalklet of its own : and the stalk- 

 let is often jointed (or articulated) with the main leaf-stalk, just sis 

 this is jointed with the stem. When this is the case, there is no 



doubt that the leaf is compound. But when the pieces have no 

 stalklets, and are not jointed with the main leaf-stalk, the leaf may 

 be considered eillier as simple and divided, or compound, according 

 to the circumstanced. 



FIG. ]2f). Pinnate with an odd leaflet, or odd-pinnate. 

 128. Abruptly pitiaata leaf. 



127. Pinnate with a tendril 



