96 A TEXT-BOOK OF GRASSES 



(Cyperaceae). Many sedges have grass-like blades, but 

 differ in having 3-ranked leaves and in having flowers 

 supported by a single bract. In rushes (Juncaceae) the 

 essential organs of the flowers are surrounded by a small 

 greenish 6-parted perianth, and the fruit consists of a 

 capsule with several or many seeds. A few plants belong- 

 ing to the lily family and other allied groups have grass- 

 like blades, but the flowers possess a proper perianth that 

 is sometimes greenish but often conspicuously colored. 

 Famihar examples of plants belonging to the grass 

 family are, blue-grass, timothy, redtop, wheat, rice and 

 other grains, corn, sorghum, sugar-cane and bamboos. 



119. Gross anatomy. — It is assumed that the student 

 is familiar with the fundamental distinction between the 

 primary organs of the phanerogams. He may be reminded, 

 only, that the plant consists of shoot and root, that the 

 shoot consists of the stem and leaves borne upon it, and 

 that the inflorescence consists of modified shoots. 



Grasses may be annual or perennial. In cooler regions 

 certain annual species may germinate in the fall, live over 

 winter as a small tuft and send up flower stalks the follow- 

 ing spring. These are known as winter annuals. 



120. Perennial herbaceous species are mostly of two 

 kinds. In the first kind a crown is formed by the per- 

 sistent bases of the culms, the upper portions of which die 

 back each year. The young shoots of the ensuing season 

 are produced from buds arising within the sheaths They 

 grow up alongside the old stems and together form a 

 compact mass. Such grasses form tufts or tussocks and 

 are commonly called bunch-grasses. The orchard-grass 

 is a familiar example. Some authors refer to the shoots 

 of bunch-grasses as being intravaginal. 



In the second kind of perennial, the new shoots arise 



