242 



CLASSIFICATION 



able to penetrate to the nectar. The mechanism of 

 the flowers of Vinca rosea, tagar and malati, excludes 

 autogamy and induces allogamy. 



Nat. Order 15. Asclepiadacece. — Herbs or shrubs, 

 usually twining, with milky juice. Leaves usually 

 opposite, entire. Sepals 5, connate in an inferior 

 calyx. Petals 5, connate, lobes valvate, throat of the 

 corolla with a corona of hairs, scales, or processes. 

 Stamens 5, the filaments united in a hollow column 



Fig. 208. — Akanda {Calotrofiis gigantea) 

 st. Stigma. «, Anther, d. Disk, t, Caudicle. /, Pollinia. ror, Corona. 



enclosing the style; anthers adnate to the stigma 

 (gynandrous), pollen-grains aggregated into i or 2 

 pollinia in each anther-lobe, the pollinia being united 

 in pairs or fours to a gland (retinaculum) on the 

 stigma. Carpels, fruits, and seeds as in Apocynacece. 

 The Order is chiefly tropical. Common plants: 

 akanda or madar [Calotropis giganted) (fig. 208); C. 

 procera or safed akanda; ananta-mul or Indian Sar- 

 saparilla {Hemidesmus indicus), a thin twining shrub; 

 Stephanotis floribunda, a large garden climber with 

 handsome white fragrant flowers; different species of 

 Hoya, which are twining epiphytes with thick coria- 



