114 WHEAT. 



which are wheat, rye, barley, oats, maize (Indian corn), rice, 

 and sugar-cane, as well as bamboo and reeds. We also place in 

 this family different herbs which constitute the bottom-grass of 

 all natural prairies, such as fescue, alopecurus (from the Greek, 

 alopeXj a fox, and oura, tail, fox-tail), timothy, festuca, meadow- 

 grass, and darnel or tare (jig. 136). 



48. Common wheat Tri'ticum the most important of all 

 the grasses, is an herbaceous annual plant, with a stem (culm) 

 four or five feet high, furnished with some leaves, which is ter- 

 minated by a spike composed of flowers united in groups of from 

 three to six, called spikelets, in a common enve- a a 

 lope, which consists of two scales, bearing 



the common name of glume; each flower 



bears three stamens enclosed between two 



unequal palese (from the Latin, palea, chaff), 



the external of which often but not always 



terminates in a long beard or barb, called 



awn (fig. 138 a). The seed is oval, larger 



than that of most other grasses, convex on 



one side, and on the other hollowed by a 



longitudinal groove ; on an average, there 



are forty seeds on each spike. It is filled 



by a white, farinaceous substance, chiefly 



consisting of fecula, and a peculiar sub- . 13 o_ 



stance named gluten. These two substances, 



crushed by a mill-stone, constitute the flour which we use for 



making bread. Fecula consists of minute grains, filled with a 



matter of a gummy consistence, which, by the action of heat 



and various chemical agents, burst and permit their contents to 



escape ; this is the reason why, when we boil fecula in water, it 



suddenly thickens and becomes paste. Gluten is a very elastic 



substance, which may be separated from fecula by washing 



wheat flour, wrapped in a cloth, under a stream of water, for 



some time. 



49. Wheat is sown at two different periods; in the autumn 



Explanation of Fig. 138. The glume or husk ; a, a, the awns; g, g, 

 the glume. This term is most generally applied to the outer and thicker 

 set of scaly leaves next to the sexual organs in grasses, two in number, and 

 embracing each other at the base (fig. 138), in which are seen the outer 

 scales (glume or calyx, g, g) and the inner scales with the awn (a) attach- 

 ed. The stamens and pistils are removed. The small thin leaves to which 

 the awns are attached, are called palea. When these scaly leaves embrace 

 several flowers, they are called bractese (bracts). 



48. What are the characters of wheat? What is a glume? What ia 

 meant by the paleae ? What is fecula ? What is gluten ? 



49. What is the difference between fall and spring wheat ? 



