TRITICUM 51 



MONOCOTYLEDONS 



This subdivision includes those plants in which the seeds con- 

 tain but a single cotyledon, the leaves are usually parallel-veined, 

 the flowers are mostly 3-merous and in the stems the fibrovascular 

 bundles are of the concentric type. 



GRAMINRE, OR GRASS FAMILY 



These are mostly herbs with cylindrical, usually hollow stems 

 (culms) closed at the swollen nodes. The leaves are alternate, the 

 basal portion or sheath enveloping the culm and bearing at the orifice 

 an appendage called the ligule. Under the epidermis of both stems 

 and leaves there is a more or less strongly developed ring of scleren- 

 chymatous fibers; similar fibers surround the concentric fibrovas- 

 cular bundles which occur in 1 or 2 circles beneath the endodermis. 



TRITICUM Couch Grass, Dog Grass, or Quick Grass. 

 The rhizome and roots of Agropyron (Triticum) ripens, a common 

 perennial grass indigenous to Europe and Asia, and naturalized in 

 North America except in the Arctic regions. It forms slender jointed 

 rhizomes, by means of which the plant is extensively propagated; 

 the culms vary from 0.3 to 1 M. in height, the spikelets have 3 to 7 

 flowers; and the empty glumes are 5- to 7-nerved, acute or with an 

 awn-like summit. The rhizome is gathered in spring, usually deprived 

 of the rootlets, cut into pieces and carefully dried. The commercial 

 supplies come chiefly from central Europe. 



Description. Horizontal, somewhat cylindrical or 4- to 6-angled, 

 usually cut into pieces 5 to 8 mm. long, 1 to 2 mm. in diameter; 

 externally light yellow, longitudinally furrowed, smooth, shiny, 

 nodes with circular leaf -scars and few root-scars; fracture tough, 

 fibrous; internally, bark light brown, about 0.5 mm. thick, wood light 

 yellow and porous, center hollow; odor slight, taste sweetish, slightly 

 acrid. 



Roots filiform, irregularly branching, attaining a length of 5 cm. 

 and not more than 0.5 mm. in thickness, light brown or yellowish- 

 brown, frequently covered with long root-hairs. 



Inner Structure. (Fig. 19.) Epidermis of a single row of strongly 

 lignified cells; hypodermis of 3 to 6 rows of strongly lignified cells; 

 cortex of thin-walled parenchyma and a few small fibrovascular bun- 

 dles; endodermis, the lateral and inner walls being thick, porous, 

 and strongly lignified; fibrovascular bundles collateral, with several 

 large tracheae and imbedded in a layer of sclerenchymatous fibers; 



