CLASSIFICATION OF ANGIOSPERMS. 301 



world, particularly in the Tropics. The plants of a numher of 

 species are used as forage, as those of clover (Trifolium) ; some 

 are cultivated as ornamental plants, as sweet pea (Lathyrus odor- 

 atits), and some yield valuable timber, as the locust (Robinia), 



XVI. ORDER GERANIALES. 



This order includes a number of families of economic import- 

 ance. The sepals are mostly distinct ; the stamens are few ; the 

 carpels are united, and the ovules are pendulous (epitropous). 



a. GERANIACE^ OR GERANIUM FAMILY. The 

 plants are herbs with alternate or opposite, usually stipulate 

 leaves, regular and perfect flowers, and capsular fruit (Fig. 

 89. C). 



Geraniuui jiiaciilattiin is a perennial herb (Fig. 155) with a 

 short, thick, horizontal rhizome, from which arises a simple, some- 

 what branching, hairy stem, with 3- to 5-parted, variously toothed 

 and cleft, petiolate leaves, those on the upper part of the stem being 

 opposite; the flowers are regular and 5-merous, occurring singly 

 or in twos in the axils of the leaves ; the petals are rose-purple 

 and hairy at the base ; the fruit is a dehiscent capsule ; the five 

 carpels when ripe separate and roll upwards remaining attached 

 to a central column by means of a slender carpophore, the indi- 

 vidual carpels being in the nature of akenes. The rhizome con- 

 stitutes the official geranium (p. 505). 



The cultivated geraniums belong to the genera Pelargonium, 

 and some of the species furnish oil of rose geranium, as P. odora- 

 tissimiiiii. P. capitatiiui and P. raditla, all of which are cultivated 

 in France, Spain, Germany, Algiers and Reunion for the oil, which 

 is largely used in perfumery. The oil contains geraniol. cit- 

 ronellol, and various esters. The leaves of Pelargonium peltatnm, 

 growing in certain parts of Africa and Australia, contain oxalic 

 acid and acid oxalates. 



b. OXALIDACE^ OR WOOD-SORREL FAMILY. To 

 this family belongs the genus Oxalis, some species of which have 

 leaves that are quite sensitive to light as well as mechanical 

 stimuli, which applies especially to the cultivated forms of South 

 Africa, and to the common wood-sorrel {Oxalis Acetosella) of 



