458 



ILLUSTRATIONS OF THE NATURAL ORDERS. 



(Periwinkle), Nerium (Oleander), and a great number of tropical 

 shrubs and trees. In nearly all, the juice is drastic or poisonous ; 

 it often yields Caoutchouc ; which in Sumatra is obtained from Ur- 

 ceola elastica, and in Madagascar from Vahea. Strangely enough 

 some species yield a sweet and harmless milk, such as Tabenirc- 

 montana utilis, one of the South American Cow-trees. Also the 

 fruit of several species is edible and even delicious ; that of others 

 is a deadly poison. One kernel of Tanghinia venenifera of Mad- 



agascar will kill twenty people. The inner bark of Dogbane makes 

 a strong cordage, whence its name of Indian Hemp. 



887. Ord. AscIcpiadaceE {Milkweed Family). Herbs or shrubs, 

 with milky juice, and mostly opposite entire leaves ; mainly differ- 

 ing from the preceding order (as they do from all other Exogenous 

 plants) by the peculiar connection of the stamens with the stigma, 

 and the cohesion of the pollen into wax-like or granular masses, 

 which are attached in pairs to five glands of the stigma, and re- 

 moved from the anther-cells usually by the agency of insects (Fig. 

 541—545). Fruit consisting of two follicles. Seeds usually with 

 a silky coma and a large embryo. — Ex. Asclepias (Milkweed, or 

 Silkweed). The juice of the A. tuberosa (Pleurisy-root, Butterfly- 

 weed) is 'not milky. In all, it is bitter and acrid, and contains 

 Caoutchouc. The roots, &c. are diaphoretic, emetic, or cathartic. 

 The inner bark yields abundance of very long and fine, extremely 



FIG. 1064 Apocynum androsasuiifolium. 10G5. Flower, of the natural size. 1066 Sta- 

 mens with the anthers conniveut around the pistils 1067. The pistils with their large com- 

 mon stigma. 1068. Seed with its coma, or tuft of silky hairs. 



