592 SYSTEMATIC BOTANY. 



Sub-order 2. Memjanthece. — Corolla plaited, or indiiilicate. Ex' 

 amples: — Menyanthes, Villarsia. 



Distribution and Numbers. — They are found in nearly all parts 

 of the world, inhabiting both the coldest and hottest regions. 

 There are upwards of 500 species. 



Properties and Uses. — A bitter principle almost universally 

 pervades the plants of this order ; hence many of them are tonic, 

 stomachic, and febrifugal. 



Erythrcea Centaurium, Common Centaury, is an indigenoiis plant possess- 

 ing similar properties to Gentian. It was till lately officinal in our pharma 

 copceias. Other species have similar properties. 



Exacum. — Various species of this genus, as E. bicolor, E. pendtinculatum, 

 &c., natives of the East Indies, possess the tonic and stomachic properties 

 of Gentian, and may be substituted for it. 



Frasera carolinensis or F. Walteri. — The root is officinal in the Pharma- 

 copoeia of the United States. It is known as American Calumba. It has 

 much less bitterness than Gentian root ; and though simUar in properties, it 

 is less powerful. It has been sold for Calumba in France, and is hence 

 texmeA false Calumba. 



Gentiana lutea. — This plant is a native of the mountains of central and 

 southern Europe. Its root is our officinal Gentian, so well known for its 

 bitter tonic properties. The roots of other species of Gentian are frequently 

 mixed with it, as those of O. purpurea, G. punctata, and G. pannonica ; the 

 admixture is, however, of little consequence, as they all possess similar pro- 

 perties. From Gentian root, the Swiss and Tyrolese prepare a spirit which 

 is mucb prized by them as a stomachic. Other Gentians have similar pro- 

 perties. 



Menyanthes trifoUatn, Buck-bean, Bog-bean, or Marsh Trefoil.— The leaves 

 and rhizome are tonic and astringent, and in lai-ge doses cathartic and 

 emetic. The plant his been employed in some parts of Germany as a sub- 

 stitute for hops. It was till lately officinal in our pharmacopoeias. 



Ophelia (Agathotes) Chirafa, the Chiretta or Chirayta.— The dried plant 

 and root possess great bitterness. Chiretta is used by the natives of India as 

 Gentian is employed in Europe. It is also in use as a tonic, &c. in this coun- 

 try, and is officinal in the British Pharmacopoeia. Other species, natives of 

 the East Indies, have similar properties. 



Stbbatia angularis, American Centaury. — The herb and root are employed 

 in the United States for their tonic and febrifugal properties. 



Natural Order 149. Asclepiadaceje. — Tlie Asclepias or Milk- 

 weed Order {_fgs. 968-970). — Character. — Shrubs or herbs, 

 commonly milky, and frequently of a twining habit. Leaves 

 entire, exstipulate. Flowers regular {figs. 968 and 969). Calyx 

 and corolla 5-partite {figs. 968 and 969); cestivation of the latter 

 imbricated, or rarely valvate ; the calyx persistent {f^g. 551), the 

 corolla deciduous. Stamens 5 {fig. 968), alternate with the lobes 

 of the corolla ; filaments usually comljined so as to form a 

 tube round the pistil {fig. 969), sometimes distinct; ^'pollin 

 when the anther dehisces, cohering in masses {fig. 551, h), and 

 sticking to 5 processes of the stigma {fig, 551, p) by twos, or 

 fours, or singly." Ovary {fig. 968) formed of 2 carpels, which 

 are more or less adherent below, but distinct above ; styles 2 ; 

 stigmas united and expanded into a fleshy 5-cornered head, the 

 pollen masses adhering to gelatinous processes arising from itg 

 angles {figs. 561, s, and 969). Fruit consisting of 2 follicles, or 



