FORMS OF SIMPLE LEA.VES. 



85 



maimer, as in Cinnamon and Melastoma (fig. 173). There is occa- 

 sionally an obscure rib running close to the edge of the leaf, and 

 called intramarginal, as in the Myrtle. 

 2. Divergent. Ribs diverging or proceeding in a radiating manner (iig. 159). 

 This is called radiating venation, and is seen in Sycamore, Vine, 

 Geranium, Castor-oil plant (flg. 161). 



B. ^—Parallel Venation. — The term parallel is not strictly applicable, for the veins 



often proceed in a radiating manner, J)iit it is difficult to find a 

 comprehensive term. This venation may be characterised as iiot 

 reticulated. 



I. Veins proceeding transversely from midrib to margin, usually with convexity 



towards the midrib, as in Musa (fig. 150) and Canna. 



II. Veins proceeding longitudinally from base to apex. 



1. Veins more or less convergent (fig. 188), as in Iris, Lilies, Grasses (fig. 



210). 



2. Veins more or less divergent, as in Fan Palms. 



C. — Furcate Venation {/urea, a fork). Veins dividing in a forked manner, as in 



the case of many Ferns. 



Forms of Leaves. 



Leaves are divided into simple and compound. The former have 

 no articulation beyond the point of their insertion on the stem or 



Kg. 151. 



Fig. 162. 



Fig. 163. 



branch, and consist of a single blade, which, however, may be vari- 

 ously divided (figs. 151, 152, 153, etc.) The latter have one or more 

 articulations beyond the point of their insertion on the stem, and con- 

 Fig. 161. Leaf of Ulmus efFusa. Betioulated venation ; primary veins going to the margin, 

 which is serrated. Leaf unequal at the Ijase. Fig. 152. Pinnatifld leaf of Valeriana dioioa. 

 Fig. 168. Bipinnatifld leaf of Papaver Ai-gemone. Feather-veined. 



