GENTIANACEAE APOCYNACEAE 



691 



Poisonous properties. Buckbean is bitter and suspected of being poisonous. 

 It causes nausea, and contains the substance menyanthin C 33 H_ O 14 , in the 

 green parts of the plant. 



Fig. 397. Buckbean (Menyanthes tri- 

 foliata). This plant is said to be more 

 or less poisonous. It is very common 

 in low lands. (Charlotte M. King.) 



APOCYNACEAE. Dogbane Family 



Perennial herbs; shrubs or vines with acrid or milky juice; entire, mainly 

 opposite leaves; without stipules; and perfect, regular 5-parted flowers; the 

 5 lobes of the gamopetalous corolla convolute and twisted in the bud; stamens 

 as many as the lobes of the corolla, alternate with them and inserted on the 

 tube, or throat; pollen granular; ovary superior, with 2 distinct ovaries; fruit 

 follicles or drupes ; seeds with a large straight embryo, often bearing a tuft of 

 hairs. About 125 genera and 1000 species. Very widely distributed, chiefly in 

 the tropics. 



The best known representative, perhaps, under cultivation is the oleander 

 (Nerium Oleander} from the Levant, naturalized in Southern Europe, the 

 Southwest and Mexico, and the Nerium odorum, of India. The periwinkles, 

 rinca minor and Vinca major, are common in cultivation, the most widely 

 distributed being the common periwinkle {Vinca minor) erroneously called 

 myrtle, found especially in country gardens and running wild in cemeteries and 

 shady places. Some species of Gynopogon have a cumarin-like fragrance. 

 Rubber is obtained from Ochrosia, Landolphia, Kickxia, Hancornia, Urceola and 

 others. Of the medicinal species, the Alstonia, or Dita Bark, is a handsome 

 forest tree from SO to 90 feet high : common throughout the Indian Peninsula 



