DICOTYLEDONES— DISCIFLOR^ 



313 



tropical America. Illustrative Genera : — Oxalis, Linv. ; Aver- 

 rhoa, Linn. There are about 830 species. 



Properties and Uses. — Chiefly remarkable for their acid juice, 

 which is due to the presence of binoxalate of potassium. The 

 fruits of some are eaten by the natives in the East Indies, but 

 they are too acid to be generally acceptable to Europeans. 



Order 95. Rutace^, the Eue Order. — Character. — Trees, 

 shrubs, or rarely herbs. Leaves exstipulate, simple or compound, 

 dotted. Flowers perfect or polygamous, regular. Calyx having 

 3_5 segments, imbricate. Petals equal in number to the 

 divisions of the calyx or wanting, rarely combined so as to form 

 a gamopetalous corolla ; cpstivation usually twisted, rarely val- 



Fift. 1084. 



Fig. 1085: 



Fig. 1086. Fig. 1087. 



Fig. 1084. Diagram of tlie flower of the Orange {i'itniK Anranlium). Fig. 



1085. Vertical section of the pistil, showing a portion of tlie disc at its 



base, and a solitary hypogj'noiis stamen. Fig. 1086. Pistil of the Orange, 



with disc at its base, and the calyx : the petals and stamens have been 



removed. Fig. 1087. Vertical section of the seed of the Common Rne 



(Riiln graveolpn.^). 



vate. Stainens distinct, or more or less united into one or 

 several bundles, equal in number to or twice as many as the 

 petals, or some multiple of them, or rarely fewer by abortion. 

 Disc annular or cup-shaj)ed, glandular, hypogynous. Ovary 

 sessile, or raised on a gynophore ; it is composed of from 2 to 5 

 carpels, which are either distinct or united so as to form a com- 

 pound ovary having as many cells as there are component 

 carpels; style simple or divided towards the base; ovules '2,, 4t, 

 or rarely more in each cell. Fruit capsular, its carpels either 

 united or more or less distinct, or succulent and indehiscent, 

 and in AurantiecE forming a hesperidium. Seeds solitary or in 

 pairs ; albumen present or absent ; radicle superior. 



Diagnosis. — Leaves exstipulate. dotted. Flowers perfect 



