158 



OBGANOGEAPHY. 



than on the other, the leaf is termed unequal or oblique {figs. 309 

 and 311) ; this is remarkably the case in the species of Begonia 

 {fig. 312). Generally speaking the leaves with ribbed, parallel, 

 or feather- veined venation are longer than broad ; while those 

 which are radiated or palmately-veined are more or less 

 rounded. When the lamina of a leaf is nearly of the same 

 breadth at the base as near the apex, narrow, and with the two 

 margins parallel {figs. 289, a, and 313), the leaf is called linear, 

 as in the marsh Gentian {Gentiana Pneumonanthe) and most 

 Grasses ; when a linear leaf terminates in a sharp rigid point 



Fig. 311. 



Fig. 314. 



Fig. 317. 



Fig. 31 



Fig. 319. 



Fig. 320, 



Fig 311. Leaf of Elm, with its margin biserrate, and unequal at its base. 



Fig. 312. Unequal or oblique leaf of a species of Begonia. Fig. 



313. Linear leaf of Goose-grass (GaUnm Aporine). Fig. 314. Lanceo- 

 late leaf. Fig. 315. Acerose or needle-shaped leaves of Juniper (Juni- 



perun communis). Fig. 316. A cuneate and mucronate-pointed leaf. 



Fig. 317. Cordate and acuminate leaf. Fig. 318. Oblong leaf of 



Bladder-Senna {Colatea arborescens). Fig. 319. Ovate leaf, with its 



margin serrated. Fig. 320. Obovate leaf. 



like a needle, as in the common Juniper {Juniperus communis) 

 {fig, 315), and many of our Pines, Rrs, and Larches, it is 



