So 



CHAP. 



IV. 



MAIZE 



69. The Leaf and Its Functions. — The leaves are borne on 

 the stem around which the sheath (Figs. 12c and 25), or lower 

 portion of the leaf, is closely wrapped ; the broad upper portion 

 which spreads away from the stem is called the blade (Figs. 1 2B 

 and 26c). At the junction of sheath and blade there is a pro- 

 jection which clasps the stem, and which is called the ligule 

 (Figs. 25 and 26). To a certain extent the ligule of the maize 

 plant checks the entrance of water and soil, which might start 

 decay between the sheath and the stem. 



Fig. 24. — Tassels of sucker-shoots, bearing small round grains as well as 

 the normal male spikelets. 



The leaf blade of the maize plant is long, broad, and 

 flat, with wavy margins ; the mid-rib is broad and strong 

 (Fig. 5). The surface is usually more or less rough with 

 scattered, adpressed white hairs (Fig. 25), which may be short 

 or longer. The cuticle is found by Wager (1) to form a thin 

 layer on both surfaces, with practically no difference in thick- 

 ness in the different breeds. 



In the dent variety of maize the number of leaves on a 

 stem usually varies from 12 to 18, but as the lower leaves die 

 off before maturity, it may happen that only about 12 function 



