LEADING FAMILIES OF FLOWERING PLANTS 357 



from a single plant sometimes weigh as much as thirty pounds. 

 The ground or sliced roots are largely fed to horses, cattle, 

 and hogs. One of the most valuable species has an acrid poi- 

 sonous juice, which must be removed by heatmg or drymg the 

 ground-up roots before they are fed 

 to animals. 



Medicinal substances in considerable 

 number — especially cascarilla bark, 

 castor oil, and croton oil — are ob- 

 tained from euphorbiaceous plants. 



India rubber is largely obtained 

 from two South American species of 

 Hevea, a plant of this family (Fig. 

 293). 



Ornamenfrd. plants of the Spurge 

 family are several species of JSnjjhor- 

 bia (Fig. 292, I), one of them com- 

 monly known as Poinsett ia, and the 

 castor bean, which in warm climates 

 grows to be a small tree, but with us 

 is a large annual. 



327. The Parsley or Carrot family 

 {Umbellifera). TheParsleyfamily com- 

 prises about 1300 species, — herbs 

 which are mostly natives of temper- 

 ate regions in the northern hemi- 

 sphere. The structure of the flowers 

 and fruit can be understood from 

 Fig. 295. As the flowers are usually 

 much alike, the distinctions between species are based upon 

 the form and structure of the fruit. ]\Iany species have 

 poisonous qualities; some — as the poison hemlock (^Conium'), 

 asafoetida, anise, and coriander — ha^'e medicinal value. The 

 carrot, parsnip, celery, and fennel are of considerable impor- 

 tance as food substances, and parsley leaves and caraway fruits 

 (" seeds ") are much used for their flavoring qualities. 



*-%■*■>' * '''' ^^ 



Fig. 293. Hevea tree tapped 

 for India rubber 



After Freeman and Chandler 



