KINDS AND FORMS OF LEAVES. 



45 



Nor are what we call reins to be likened particularly to the bloodvessels of ani- 

 mals. But this name is not so bad ; for the minute fibi'es which, united in bun- 

 dles, make up the ribs and veins, are hollow tubes, and serve more or less for con- 

 veying the sap. 



125. As to the veining, or the arrangement of the framework in the blade, leaves 

 are divided into two classes, viz. : \si, i\\e Netted-veined or Retictdated, and, 2d, 

 the Parcdlel-veined or Neri-!ed. 



126. Netted- Vcineil or Reliculatert leaves are those in which the veins branch off 

 from the rib or ribs, and divide again and again, and some of the veins and veinlets 

 run into one another, 



so forming reticvdations yTTTTlTJ -=^^^32 



or meshes of network 



throu2;hout the leaf. 



Tins is shown in the 



Quince-leaf (Fig. 82) ; 



also in the Linden or 



Basswood (Fig. 83), 



and the Maple (Fig. 



84), where the finer 



meshes ajipcar in one 



or two of the leaves. 



127. Netted-veined 

 leaves belong to plants 

 which have a pair of 

 seed-leaves to their em- 

 bryo (48), and stems 

 of the exogenous structure (115). That is, these three kinds of structure, in em- 

 bryo, stem, and leaf, generally go together. 



128. Parallcl-YCillcd or Nerved leaves are those in which the ribs and veins run side 

 by side without branching (or with minute cross-veinlets, if any) from the base to 

 the point of the blade, as in Indian- Corn, Lily of the Valley (Fig. 85), &c., or 

 sometimes from the midrib to the margins, as in the Banana and Calla (Fig. 8G). 

 Such parallel veins have been called Nerves, as just explained (124). Leaves of this 

 sort belong to plants with one cotyledon to their embryo (47), and with endogenous 

 stems (113). 



83. Linden. 



Netted-veined Leaves of 



84. Maiile, 



