CISTACE^E VIOLACE^E. 3(55 



orellana supplies the substance called arnotto, which is used for yield- 

 ing a red colour, and for staining cheese. There are 31 genera, and 

 85 species, according to Lindley. Examples Patrisia, Flacourtia, 

 Prockia, Erythrospermum, Bixa. 



767. Order 17. eistacete, the Rock-Rose Family. (Polypet. Hypog.) 

 Sepals usually 5, persistent, unequal, the three inner with contorted 

 aestivation. Petals 5, caducous, hypogynous, aestivation corrugated, and 

 twisted in an opposite direction to that of the sepals. Stamens usually 

 00, free, hypogynous ; anthers 2-celled, adnate. Ovary syncarpous, 

 1- or many-celled ; style single ; stigma simple. Fruit capsular, 3-5- 

 10-valved, either 1-celled or imperfectly 5-10-celled, with loculicidal 

 dehiscence. Seeds usually indefinite ; embryo inverted, either spiral 

 or curved, in the midst of mealy albumen; radicle remote from the hilum. 

 Shrubs or herbaceous plants with entire, opposite or alternate, stipu- 

 late or exstipulate leaves. They inhabit chiefly the southern regions 

 of Europe, and the north of Africa. Some of the species are remark- 

 able for the irritability of their stamens (^[ 665). Many of them 

 yield a resinous balsamic juice, which imparts viscidity to the branches. 

 The resinous matter called ladanum or labdanum, is yielded by Cistus 

 creticus. There are 7 known genera, and 185 species, according to 

 Lindley. Examples Cistus, Helianthemum, Lechea. 



768. Order 18. vioiaccte, The Violet Family. (Polypet. Hypog.} 

 Sepals 5, persistent, usually elongated at the base, aestivation imbri- 

 cated. Petals 5, hypogynous, equal or unequal, generally withering, 

 aestivation obliquely convolute. Stamens 5, alternate with the petals, 

 sometimes opposite to them, inserted on a hypogynous torus ; anthers 

 dithecal, introrse, often cohering, with a prolonged connective some- 

 times spurred (fig. 343); filaments dilated, two of them in the irregular 

 flowers having an appendage at their base. Ovary unilocular, with 

 many (rarely one) anatropal ovules ; style single, usually declinate, with 

 an oblique hooded stigma (fig. 390, 1 s). Fruit a 3-valved capsule, 

 dehiscence loculicidal, placentas on the middle of the valves (fig. 390.) 

 Seeds 00 or definite ; embryo straight, erect, in the axis of a fleshy 

 perisperm. Herbs or shrubs, with alternate, rarely opposite, leaves, 

 having persistent stipules, and an involute vernation. They are 

 natives of Europe, Asia, and America. The herbaceous species 

 inhabit chiefly the temperate parts of the northern hemisphere, 

 while the shrubby species are found in South America and India. 

 They have been divided into two suborders: 1. Violeas, with irregular 

 flowers. 2. Alsodeiea3, with regular flowers. There are 14 known 

 genera, and 315 species. Examples Viola, lonidium, Alsodeia. 



769. They are distinguished by the emetic properties of their roots, 

 which contain an active principle called violine, similar in its qualities 

 to emetin. The roots of Viola odorata have been used medicinally as 

 emetics. Some species of lonidium are used in South America as substi- 



