386 



MANUAL OF BOTANY 



appendages (fi(j- 1156, ^j), the pollen of each anther-lobe 

 forming a polliniinn ; the right-hand pollinium of each anther 

 united to the left-hand one of the contiguous anther by a 

 gummy process formed by the stigma {fig. 1153, h). Ovary 

 superior, of 2 carpels, which are more or less adherent below, 

 but distinct above ; styles 2 ; stigmas united and expanded into 

 a fleshy 5-cornered head, the processes joining the poUinia 

 arising from its angles. Fruit consisting of 2 follicles, or 1 by 

 abortion. Seeds numerous, generally comose, with thin albumen. 



Diagnosis. — This order is distinguished amongst the Di- 

 carpise by its curiously formed stigma and adhering poUinia. 



Distribution and Numbers. — They are chiefly tropical plants, 



Fig. 1153. 



Fig. 1154. Fig. 1155. Fig. 1156. 



Fig. 1153. Pistil of a species of Asclepias, witli the polliuia, 2^, adliering to 



the stigma, ». b. Pollen-masses as detached from contiguous anthers. 



Fig. 1154. Diagram of the flower of Asclfpias nivca. Fig. 1155. Flower 



of a species of Asdi^jiias, with the stamens united and forming a tube 



round the pistil. 2^- Corolla, a. Appendages of the stamens. Fig. 



1156. One of the stamens of the same removed. /. Filament, a. Anther. 

 2). Hornlike appendage of the filament. 



abounding in southern Africa, India, and equinoctial America. 

 A few occur in Southern Europe. Illustrative Genera: — 

 Hemidesmus, -B. Br.; Asclepias, ir;«w.; Hoya, i?. 5r. ; Stapelia, 

 Linn. There are about 1,000 species. 



Properties arid Uses. — The plants of this order are chiefly 

 remarkable for their bitter acrid juice, which renders them 

 stimulant, emetic, purgative, and diaphoretic. Several species 

 are reputed to be antidotes to snake-bites. Some species .yield 

 Caoutchouc ; but no important commercial kind of Rubber is 

 obtained from them. Parts of some are edible, as the roots 

 of Gomphocarpus jjedunculatus, and the tubers of Ceropegia 

 Vignaldiana, ike. 



