492 



ANGIOSPERMS 



weeds that are poisonous. The Horse Nettle (Solanum caro- 

 linense) (Fig. 44%) is troublesome on account of its spiny stems, 

 and it has a deep rootstock, which is difficult to eradicate. 

 Another troublesome weed of this family is the Buffalo Bur 



(Solanum rostratum) (Fig. 

 443), which has spiny fruits 

 that catch into the wool and 

 hair of livestock. 



The Madder Family 

 (Rubiaceae). This is one 

 of the largest families of the 

 Dicotyledons. There are 

 more than 4000 species be- 

 longing to this family, but 

 the majority of them are 

 tropical. They include 

 herbs, shrubs, and trees. 

 Their flowers are epigynous, 

 and the stamens and lobes 

 of the calyx and corolla 

 are the same in number 

 (usually 4-5). 



The Coffee tree (Fig. 444), 

 which is grown extensively 

 in Brazil, Arabia, and Java, 

 is the most important plant 

 of the family. The fruit 

 (Fig. 445} of the Coffee tree 

 is a cherry-like drupe containing two seeds, and these seeds are 

 the coffee of commerce. The Cinchona tree, growing wild in 

 the Andes and cultivated in India, furnishes Cinchona bark 

 from which quinine is made. 



Gourd Family (Cucurbitaceae). This family includes the 

 Gourds, Pumpkins, Squashes, Melons, and Cucumbers. The 

 flowers are epigynous, and the plants are monoecious or dioecious 

 (Fig. 6). The stamens are usually more or less united. In 

 our region there are only a few species of this family and none 

 of much importance except those mentioned above. 



Composite Family (Compositae). This is an immense fam- 

 ily and is of world-wide distribution. It is the highest group 



FIG. 443. A plant of the Buffalo 

 Bur bearing flowers and fruits, showing 

 the character of the plant ( X T V) ; and a 

 single flower, showing the prickly calyx 

 and gamopetalous corolla. After Dewey. 



