280 MEDICAL BOTANY. 



geniculate above the middle, lower portion glabrous, persistent, uncinate after the upper 

 portion falls off. Fruit a cluster of dry achenia, which are oval, brown, smooth, having a 

 tail or awn formed of the persistent styles, twisted and uncinate at apex. 



This plant is found in woods and along streams in most parts of the 

 United States. The flowers are small, and few in number ; and the leaves 

 are exceedingly various in their mode of division, and, like the stipules, vary- 

 much in size. The whole herb is astringent, but the most efficient portion 

 is the root. This, when dried, is of a brown colour, brittle, crooked, and 

 tuberculated, white internally, of a bitterish, astringent taste, and a somewhat 

 aromatic smell, especially in the spring. No analysis has been made of it; 

 but its composition is probably very similar to that of the G. urbanum, 

 which has been shown to contain much tannin and bitter extractive, gum, 

 &c. It yields its active principles to water and alcohol, and communicates 

 a red colour to them. 



Medical Properties. — This and the other species alluded to, are tonic and 

 astringent. They are much used in some parts of Europe in a variety of 

 diseases ; and are also frequently employed, especially the G. rivale, in the 

 New England States and Canada. Both Drs. Ives and Bigelow speak of this 

 with praise in dyspepsia and debility of the visceral functions. They have 

 also been employed with some success in leucorrhoea, chronic haemorrhages, 

 &c. ; but it is evident that they might be rejected from the Materia Medica, 

 as there are many other articles of much greater value, and better capable of 

 fulfilling these indications. 



Avens is given in powder, in doses of half a drachm to a drachm, but most 

 frequently in decoction, made with an ounce of the root to a pint of water, 

 of which an ounce or two is to be taken several times a day. Another mode 

 in domestic practice is to take a weak decoction with sugar and milk, instead 

 of tea or coffee. 



The G. rivale is found both in Europe and the United States, in bogs and 

 wet meadows, and is the species generally employed in the Northern States. 

 The G. urbanum is peculiar to Europe, and has yellow flowers. 



Section 3. Spir.eid.e. — Calyx tube herbaceous. Fruit, a ring of follicles. Seeds not 

 winged. 



Spiraea. — Linn. 



Calyx 5-cleft, persistent. Stamens 10 — 50, inserted with the petals into a torus ad- 

 hering to the calyx. Carpels distinct, rarely coherent at base, sessile, rarely stipitate. 

 Seeds exalbuminous. 



This extensive genus, which has been variously divided by botanists into 

 numerous sections, and even into other genera, consists of unarmed shrubs, 

 or perennial herbs, with alternate branches, and variously-formed alternate 

 leaves, and white or red, but never yellow, flowers. The species, some of 

 which are highly ornamental, are principally natives of temperate and cold 

 climates, the largest number of them being found in Siberia and North 

 America. 



S. tomentosa, Linn. — Stem simple, shrubby, erect. Leaves ovate-lanceolate, unequally 

 serrate, tomentose beneath. Spikes terminal, compound. Flowers crowded, pentagy- 

 nous. 



Linn., Sp. PI. 701; Torrey and Gray, Fl. i. 415; Rafinesque, Med. 

 Flor. ii. 91 ; Mead, Med. Repos. 



Common Names. — Hard-hack ; White-leaf, &c. 



