GROWTH AND WORK OF PLANTS 



122. Parts of the leaf in the Indian corn and grasses. 



In the grasses the part of the leaf attached to the stem folds 



completely or partly around 

 the stem for some distance, 

 and is called the sheath, 

 while the blade is free. In 

 the Indian corn and some 

 other Graminea3 (grasses) 

 there is a membranous 

 growth arising from the 

 junction of the sheath and 

 blade which lies close around 

 the stem. This is the ligule. 

 123. Venation of leaves. 

 The blade of the leaf is 

 prominently marked by 

 lines, in the form, usually, 



Leaf of corn, showing blade, sheath, and ligule. f elevations, especially On 



D. 



Fig. 68. 



A. Leaf of apple, showing persistent stipules at base of petiole, a pinnate, reticulate, 

 veined leaf, edge serrate. B. Leaf of beech, pinnate, reticulate venation, edge serrate. C. 

 Leaf of laurel, edge plain. D. Leaf of holly, edge spiny. 



the underside, while the lines are also seen distinctly on the 

 upper side of the leaf. These are called veins of the leaf. 



