230 BOTANY AND PHARMACOGNOSY. 



arranged polygonal starch grains in which the rarified area is at 

 least from one-tenth to one-fifth the diameter of the entire grain. 

 Pieces of the pop-corn, as well as the horny portions of some of 

 the flint and dent corns, will pop as readily as the whole grains. 



(2) Zea Mays indentata yields the dent or flint corns, the 

 grains of which have a corneous (horny) endosperm on the sides 

 and are indented at the summit, owing to the shrinking of the 

 cells which contain more cell-sap and less compactly arranged 

 starch grains. 



The starch grains in the cells of the horny endosperm resem- 

 ble those of pop-corn, but the starch grains in the other cells are 

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

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

 ally not more than 2 /* in diameter. 



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

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

 wrinkled 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 arundinaceus vulgare) 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. Schoenan- 

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

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

 found in Vanilla grass (Anthoxanthum odoratum) and white or 

 Dutch clover (Hierochlce odorata). Some species of Stipa are 

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

 Africa and Spain. 



b. CYPERACE^ OR SEDGE FAMILY.— The culms are 

 mostly solid; the leaves are narrow, 3-ranked, and with closed 

 sheaths, the ligule being absent or quite small; the perianth is 

 composed of six bristles or represented by an indefinite number 

 of hairs, or entirely wanting ; the lodicules are wanting ; the fruit 

 is an akene; and the endosperm contains starch. 



