200 



BOTANY. 



cence looks like a single flower. In. the spurges, as in the 

 other members of the order, the flowers are very simple, being 

 often reduced to a single stamen or pistil (Fig. 109, M, N). 

 The plants generally abound in a milky juice which is often 



Fio. 109. Eucylae (Frangulinse) , Tricoccss. A, flowers of spindle-tree, 

 Euonymus, (Celastracese) , x l. B, cross-section of the ovary, x 2. C, dia- 

 gram of the flower. D, leaf and fruit of bitter-sweet (Celastrus), x y 2 . ] t 

 fruit opening and disclosing the seeds. F, section of a nearly ripe fruit, 

 showing the seeds surrounded by the scarlet integument (aril), em. the 

 embryo, x 1. G, flower of grape-vine, Vitis (Vitacese), x 2. The corolla 

 has fallen off. H, vertical section of the pistil, x 2. /, nearly ripe fruits 

 of the frost-grape, x 1. J, cross-section of young fruit, x 2. K, a spurge, 

 Euphorbia (Euphorbiacese) , x %. L, single group of flowers, surrounded by 

 the corolla-like involucre, x 3. M, section of the same. <?, male flowers ; 

 9 , female flowers. N, a single male flower, x 5. 0, cross-section of ovary, 

 x 6. P, a seed, x 2. Q, longitudinal section of the seed, x 3. em. embryo. 



poisonous. This juice in a number of tropical genera is the 

 source of India-rubber. Some genera like the castor-bean 

 (Ricinus) and Croton are cultivated for their large, showy 

 leaves. 



The water starworts (Callitriche) , not uncommon in stag- 



