490 BOTANY AND PHARMACOGNOSY. 



Roots somewhat tortuous, 5 to 6 cm. long, about 0.3 to 0.5 

 mm. in diameter, rootlets few. 



Inner Structure. — See Fig. 114. 



Constituents. — A bitter, somewhat crystalline glucoside, 

 convallamarin. about 0.6 per cent., which is soluble in water, 

 alcohol and ether and has a physiological action similar to digi- 

 talin. An acrid glucoside, convallarin, forming rectangular prisms 

 which are insoluble in ether and sparingly soluble in water, the 

 solution foaming on shaking like a saponin solution. 



The FLOWERS of Lily-of-the-valley contain a volatile crystalline 

 principle which is fragrant in even dilute solutions. 



CYPRIPEDIUM.— LADY'S SLIPPER.— The dried rhizome 

 and roots of Cypripedimn pubescens (C. hirsutum), and Cypri- 

 pediuni parviMorum (Fam. Orchidacese ) , perennial herbs (Fig. 

 213) native in woods and thickets of the Eastern and Central 

 United States and Canada (p. 245). 



Description. — Rhizome horizontal, somewhat tortuous and 

 bent, 3 to 7 cm. long, 2 to 4 mm. in diameter; externally dark 

 brown, annulate from scars of bud-scales, upper surface with 

 numerous large, sometimes depressed scars, under and side por- 

 tions with numerous roots and few root-scars ; fracture short ; 

 internally light brown, cortex about 0.5 mm. thick, central cylin- 

 der somewhat porous, and with numerous scattered fibrovascular 

 bundles ; odor heavy, distinct ; taste bitter, somewhat pungent. 

 The walls of the endodermal cells are but slightly cutinized. 



Roots 3 to II cm. long, 0.5 to 1.5 mm. in diameter; externally 

 light or dark brown, longitudinally wrinkled ; fracture somewhat 

 fibrous ; internally, cortex white, central cylinder yellowish. 



Constituents. — Volatile oil, several resins, a bitter glucosidal 

 principle, tannin, gallic acid, starch, calcium oxalate in the form 

 of raphides, and ash about 6 per cent. 



TRITICUM.— COUCH GRASS.— The rhizome of Agropy- 

 ron repens (Fam. Graminese), a perennial grass (Fig. 214), indig- 

 enous to Europe and Asia, and naturalized in North America, 

 except in the Arctic region (p. 227). The rhizome is gathered 

 in spring, deprived of the rootlets, cut into pieces and carefully 

 dried. Our commercial supplies come chiefly from Central 

 Europe. 



