664 A TEXT-BOOK OF BOTANY. 



(see Vol. II) with large, 5- to 7-nerved, broadly elliptical leaves. 

 The flowers are yellow and occur in axillary cymes. The fruit is 

 a 2-valved, ovoid capsule. The rhizome and roots are official. 

 Many of the gentians are among the most highly prized of the 

 wild flowers, some of them, as the fringed gentian (Gentiana 

 crinita), being one of the most beautiful. The closed gentian (Fig. 

 357), so called because the flowers remain closed, is quite abundant 

 in moist grounds throughout most of the United States and 

 Canada. The roots of a number of species of American gentian 

 have medicinal properties resembling that of G, liitea. 



Menyanthes, the yellowish-white horizontal rhizome of Men- 

 yanthes trifoliata (Fig. 363), contains an amorphous glucoside 

 which is slightly soluble in water, soluble in alcohol, and is precipi- 

 tated with tannin. Upon hydrolysis menyanthin yields a volatile 

 oil possessing an odor reminding one of bitter almonds. 



Swertia Chirata. — The entire plant is official. 



Herba Centaurii minoris, the entire plant of Erythrcca Cen- 

 taurium of Europe, contains a glucoside, erytaurin, which forms 

 small colorless prismatic and bitter crystals and is slowly hydro- 

 lyzed by emulsin. Sabbatia EUiottii, occurring in the pine barrens 

 of the Southern States, is known as the " quinine herb." 



d. APOCYNACE.^ OR DOGBANE FAMILY.— The plants 

 vary from perennial herbs to shrubs and trees, contain an acrid 

 latex, and have flowers with the stigrnas and styles united and the 

 stamens distinct. They are mostly found in the Tropics. 



Apocynmn camiabimtm is a perennial herb with erect or ascend- 

 ing branches. The leaves are oblong-lanceolate, opposite, nearly 

 sessile or with short petioles (Figs. 226, 251). The flowers are 

 greenish-white, the lobes of the corolla being nearly erect and 

 the tube about as long as the calyx. The fruit is a slender, terete 

 follicle containing numerous seeds tipped at the micropylar end 

 with a tuft of hairs. The root is official. 



The root of a closely related species, namely, spreading dog- 

 bane {Apocymmi androsccinifolium), is sometimes substituted 

 for the official drug. The plant is distinguished by being more 

 spreading in its habit. The leaves are ovate (Figs. 226, 364), the 

 flowers are pinkish, the lobes being revolute, and the tube several 

 times as long as the calyx. 



