226 



BOTANY AND PHARMACOGNOSY. 



to the base on the side opposite the blade, and with a slight pro- 

 jection at the juncture of the blade and sheath called the ligule; 

 the flowers are perfect, monoecious or dioecious, the stamens being 

 usually three in number (Figs. 125, 126). Each flower is sub- 

 tended by one to three minute hyaline scales known as lodicules, 

 and below the lodicules is a scale leaf known as the inner pale, 

 while each individual flower stalk is subtended by still another 

 scale known as the outer pale. In addition each spikelet is sub- 

 tended by one or two empty scales or glumes, the various bracts, 

 which persist, constituting the chaff. The fruit is a seed-like 

 grain, in which the seed is closely united with the thin pericarp, 



...a. 



-y— 



Fig. 124. Diagrams of cross sections of monocotyledonous flowers; t. stem of plant; 

 f, bract; s, sepals or outer circle of perianth ; p, petals or inner circle of perianth; a, stamens; 

 c, ovary. A, regular flower of the lily; B, irregular flower of iris; C, flower of an orchid, in 

 which 1 is the lip and SS the two staminodes. — After Warming. 



and is called a caryopsis (Fig. 120). The endosperm contains 

 numerous starch grains and oil, while the gluten layer around the 

 endosperm contains proteids. The number of layers of gluten- 

 or aleurone-containing cells varies in the different cereals. In 

 corn, wheat and rye it consists of but a single layer; in oat and 

 rice, of I or 2 layers ; while in barley it is made up of 2 to 4 layers. 

 The Grasses comprise about 3,500 species and are distributed 

 in all parts of the world. While most of the plants are grass-like 

 still some of them, as the bamboos of the Tropics, become quite 

 tall, having woody silicious stems and bearing many branches in 

 the axils of the leaves. They yield the cereal grains forming so 

 large a proportion of the food of man, and forage constituting the 

 food of many of the lower animals. The following are some of 



