348 Plants and their Ways in South Africa 



Small shrubs with tuberous roots. Flowers white, red, or 

 yellow. 



Order Asclepiadace/e. 



Flowers perfect, regular, five parted ; sepals imbricate, odd 

 sepal at the back. Corolla sympetalous, valvate, or rarely con- 

 volute. Stamens five; carpels two, apocarpous below but 

 sharing a single large five-angled stigma. 



This order is like Apocynaceae in general habit, latex, 

 opposite leaves, follicles, and hairy seeds. But the stamens 

 are united at base.^ In most flowers each stamen bears a 

 petal-like or tongue-like process at the back, forming a 

 crown. 



The pollen is granular or united in masses as in Orchidaceae. 

 When granular (in the smaller group, Periplocse), the pollen is 

 shed into curious horny cornucopias or spoon-like pollen 

 carriers (translators). These lie between the stamens, each 

 translator receiving pollen from a half of two anthers. At the 

 lower end of this remarkable structure is a sticky gland by which 

 it becomes affixed to a visiting insect and then discharged 

 of its pollen upon the stigma of the next flower visited. Six 

 genera of this interesting group are described found in the 

 Kalahari and Eastern regions. In most genera around the 

 stigma five small dark brown pollen carriers may be seen to 

 which pollinia are attached. The translator is the chief 

 character separating the order from Apocynaceae. In section 

 Cynanchae, the translator is y-shaped. 



By placing a needle under the glands they may be with- 

 drawn, as they are when an insect frees its foot from the slit 

 between the anthers. The glands are between the stamens, 

 and the pollen masses on either side come from the halves of 

 two adjacent anthers. 



The inflorescence is cymose or racemose. In some genera, 

 e.g. Asclepias^ the inflorescence is extra-axillary, as it is the 

 main branch that turns aside to bear the flowers. 



' Except in section Periplocas. 



