VIOLA CEJE. 139 



wards removed by scraping them with knives. As found in commerce, it is 

 very impure, containing a very large propor- 

 tion of dirt and sand. When pure, the smell 

 is balsamic and agreeable, and the taste some- 

 what bitter and aromatic. It is insoluble in 

 water, but is almost wholly dissolved by alco- 

 hol. According to Guibourt, it consists of re- 

 sin and volatile oil, 86 ; wax, 7 ; aqueous ex- 

 tract, 1 ; impurities, 6. This analysis being of 

 the pure article, differs widely from that of Pel- 

 letier, who examined this substance as usually 

 found in the shops, which afforded him but 20 Ladanum Rake, 



of resin, whilst there was 72 of sand and impu- 

 rities. 



Ladanum is now but seldom used as a medicinal agent, though it was for- 

 merly in some repute as an ingredient in several stimulating plasters, oint- 

 ments, and theriacs. Its principal employment is in perfumes, and as a con- 

 stituent in aromatic pastilles. 



Group VII. —Viol ales. 



Order 14.— VIOL ACE jE.— Be Candolle. 



Sepals 5, persistent, produced at base. Petals 5, alternate with the sepals, hypogy- 

 nous, usually unequal, the upper one generally spurred or saccate at base. Stamens 5, 

 alternate with the petals, inserted on the hypogynous disk, filaments dilated and project- 

 ing beyond the anthers, two of them usually with a gland at base. Anthers 2-celled, 

 innate, introrse, opening longitudinally. Ovary 1-celled, of 3 united carpels, with 3 pari- 

 etal placentae. Style sometimes declined or curved, with an oblique cucullate stigma. 

 Pericarp a 1-celled, 3-valved, many-seeded capsule. Seeds often with a tumour at base, 

 and a horny testa. Embryo straight in the axis of a fleshy albumen. 



The Violacese consist of herbs or shrubs, with simple, petiolate, generally 

 alternate leaves, having two stipules. The roots of almost all of them are 

 nauseous and emetic. The species of Viola are most numerous in temperate 

 climates, whilst those of Ionidium are almost peculiar to South America, 

 where many of them are known under the name of Ipecacuanha. 



Viola. — Linn. 



Sepals 5, unequal, more or less appendaged at base. Petals 5, unequal, the upper (by 

 re-supination the lower) calcarate at base. Stamens approximate, filaments distinct. 

 Anthers connate. Capsule bursting elastically. 



This extremely numerous genus is composed of small herbaceous plants, 

 which are mostly perennial, having a fleshy rhizome or subterraneous 

 stem, or a visible stem and fibrous roots. The leaves are alternate. The 

 flowers are solitary on angular peduncles, and generally blue, yellow, or 

 white. De Candolle enumerates many species, of which over 30 are natives 

 or have become naturalized in North America. The derivation of the name 

 is not known, but many conjectures have been hazarded by etymologists, all 

 of which are rather fanciful than just ; thus one says it is indicative of the 

 powerful scent of the plant, " a vi olendi ;" another insists that it is a dimi- 

 nutive of via, because " quod juxta vias nasci amat." Whatever may be its 

 derivation, the plant has been known from the earliest ages, both as a theme 

 for the poet and as a medicinal agent. 



V. odorata, Linn. — Stemless. Leaves cordate, smooth as well as the footstalks. 

 Sepals obtuse. Lateral petals with a hairy line in the centre. 



