446 



SYSTEMATIC BOTANY, 



The plants are generally somewhat acrid, and were formerly 

 supposed to be sedative. The only genus of importance is : — 



Reseda. — Reseda odorata is the Mignonette plant which is so much esteemed 

 for the fragrance of its flowers. Reseda luteola, a common plant in this 

 country, and known under the name of Weld, yields a yellow dye. 



Natural Order 18. Cistacej^. — The Kock-Eose Order {fg<i. 

 871 and 872). — Character.--*S'Ar?(fe or herbs, often viscid. 

 Leaves opposite or alternate, entire, stipulate or exstipulate. 

 Flowers showy. /Sf^rir^s usually 5 (^^. 871), sometimes 3, per- 

 sistent, unequal ; (Estivation of the three inner twisted. Petals 

 usually 5 {fig. 871), very rarely 3, caducous, hypogynous, fre- 

 quently corrugated in the bud, and twisted in a reverse way 

 to that of the sepals. Stamens {fig. 871) distinct, hypogynous, 

 definite or indefinite. Ovary 1 {fig. 871) or many-celled; style 

 single; stigma simple. Fruit capsular, usually 1-celled, with 

 3 — 5, or rarely 10 valves; or imperfectly 3—5 — 10-celled; 'pla^ 

 centas parietal {fig. 871). Seeds definite or numerous, albumi- 

 nous {fig. 872) ; emhryo {fig. 872) curved or spiral, with the 

 radicle remote from the hilum. 



Fig. 871. 



Fig. 872. 



Fig. 871. Diagram of the flower of a species of Helianthemum. Fig. 872. 



Secti(Mi of the seed of a species of Cistus, the pointed end being its 

 apex. 



Diagnosis. — Leaves entire. Sepals and petals with a ternary 

 or quinary arrangement, twrsted in aestivation ; the former per- 

 sistent, the latter caducous. Stamens hypogynous, distinct. 

 Ovary with parietal placentas ; style single ; stigma simple. 

 Fruit capsular. Seeds with mealy albumen ; embryo inverted, 

 ourv'ed or spiral. 



Distribution, ^x. — These plants are most abundant in the 

 south of Europe and the north of Africa. Some few are found 

 in other parts of the globe. Exam-ples of the Genera: — Cistus, 

 Helianthemum. There are 190 species. 



Pro]perties and Uses. — These plants have generally resinous 



