230 BOTANY AND PHARMACOGNOSY. 



more or less rounded or slightly polygonal, and vary from 5 to 25 

 fi in diameter ; the central rarified area is either wanting or usu- 

 ally not more than 2 jx in diameter. 



(3) Zca Mays saccharata yields the sugar corns. While the 

 grains are more or less translucent and horny, they have a 

 w^rinkled or shrivelled surface. The cells of the endosperm con- 

 tain gum-like substances and a relatively small number of nearly 

 spherical starch grains from 4 to 10 /x in diameter. 



Broom corn {Andropogon arundinaccus vulgar e) is a plant 

 which is cultivated for the panicles or seed heads, which are used 

 in the manufacture of brooms. This plant differs from the other 

 species of Andropogon in that the branches of the panicles are 

 longer, straighter and stronger, forming a so-called " brush." 



Quite a number of the grasses contain odorous principles, as 

 Andropogon citratus which yields lemon-grass oil; A. Scha^nan- 

 thus which yields gingergrass or geranium-grass oil; A. sqiiar- 

 rosus the rhizome of which is known as Vetiver. Coumarin is 

 found in Vanilla grass {Anthoxanthum odoratinn) and white or 

 Dutch clover {Hicrochlcc odorata). Some species of Stipa are 

 used in the manufacture of paper (Alfa or Esparto) in North 

 Africa and Spain. 



b. CYPERACE^ OR SEDGE FAMILY. These plants are 

 all herbaceous, the majority being perennial (seldom annual). 

 The rhizomes are mostly sympodial (being monopodial, however, 

 in certain Carices), and the stems are mostly solid and triangular, 

 without swollen nodes. The leaves are grass-like, generally 

 arranged in three rows, and the sheath is closed, being mostly 

 without ligules. The flowers may be hermaphrodite or uni- 

 sexual, sometimes dioecious, and arranged in spikes or racemes. 

 The perianth is wanting or only represented by six bristles, or 

 by an indefinite number of hairs. The number of stamens is 

 three, with the anthers attached by their bases to the filament. 

 The gyngecium consists of 2 to 3 carpels, with one style divided 

 into 2 or 3 branches, and provided with papillre. The fruit is a 

 nut, whose seed is generally united with the pericarp. The em- 

 bryo is small and lies at the base of the seed in the central line, 

 surrounded by the endosperm. On germination, the cotyledon is 

 freed from the seed. 



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