FOBMS OF LEAVES. 41 



Scurvy Grass affords an example of an angular leaf (fig. F) ; and 

 the Ground Ivy (fig. G), Marsh Violet, and Lesser Celandine 

 represent the kidney-shaped leaves. Of round leaves we have 

 the Mint (fig. H B) and Wintergreen. In compound leaves 



Q H 



there is the simple pinnate form, which we have already noticed 

 in the Cuckoo-Flower, &c. (Plate III., fig. 5) ; the U-pinnate, 

 where each leaflet is again divided ; the AaY-shaped pinnate and 

 bi-pinnate, as the Fennel (fig. I) ; and the tri-pinnate still more 

 divided. The grass-shaped leaf is rare, except in the second great 

 class ; but the Stitchwort affords an example among Thalami- 

 florals. The leaves of the Snowdrop, Crocus, Daffodil, &c., 

 are all grass-shaped, modified in the form of their point to 

 acute, sioord-shaped, &c. ; but these leaves have a different 

 structure. We have already spoken of one broad mark of 

 distinction between the first and second classes in the One or 

 Two-lobed form of the seed. Another distinction equally clear 

 and permanent exists in the venation of the leaf. In the Two- 

 lobed class the veins of the leaf form a network, the side veins 

 running at almost a right angle with the midrib, and the lesser 

 veins branching off in a similar manner from them. This net- 

 worlc venation belongs to the Two-lobed class. In the One- 

 lobed class the veins run parallel, starting from the footstalk 

 and continuing in a line, more or less straight, to the point. 

 This is plainly the case in all true Grasses and in the long 

 narrow leaves of the bulbous plants. It is no less really so in 

 other forms of the One-lobed foliage, as, for instance, the 



