THE DICOTYLEDONES 



1829 



V. Dirachmoldeae 



Ovary not beaked, carpels eight, calyx tubular. Dirachrna, which 

 contains a single species, found on the island of Socotra, off East Africa. 



The flowers of the genus Geranium show interesting pollination 

 mechanisms (Fig. 1732). In general the larger the flowers the more insect 

 visitors are relied upon and the more probable is cross-pollination. In the 



Fig. 1732.— Pollination in Geranium. A-D. G. molle. A, Early stage, anthers closed. 

 B Anthers dehiscing beside opening stigmas. C, Stigmas receptive. D, Anthers all 

 open. E-G. G. svlraticum. E, Female flower with abortive stamens. F Anthers 

 opening, stigmas closed. G, Anthers empty and deflexed, stigmas receptive ( 1 his was 

 Konrad Sprengel's first observation on pollination.) H-L. G.pyrenatcum. H Immature 

 stage. J, Outer stamens erect, anthers open. K, All stamens erect with anthers open. 

 L, Hermaphrodite stage with stigmas and anthers both open. {Partly after Herm. 

 Miiller.) 



