THE ANGIOSPERMAE 



1271 



A. Herkogamy. The separation of anthers and style in such a way 

 that direct autogamy is mechanically impossible. Anacamptis 

 [Orchis) pyramidalis. 



B. Dichogamy. The separation of the sexes by different times of 

 ripening. Under this heading there are two alternatives : 



I. Protandry (Hildebrand) or Proterandry (Delpino). The 

 stamens ripen before the stigmas. Many examples. Eremurus 

 (Fig. 1211). 



Fig. 121 1. — Eremurus bungei. Part of an inflorescence show- 

 ing protandry. Above are unopened flowers, next, a 

 zone of flowers with ripe stamens, and below, flowers 

 with mature styles. 



2. Protogyny (Hildebrand) or Proterogyny (Delpino). The 

 stigmas ripen before the stamens. Plantago (Fig. 1212). 

 The second alternative is less common than the first, in 

 hermaphrodite, but it occurs in all monoecious and most 

 dioecious plants. 



Heterogamy. Individual plants vary in regard to the method of 

 pollination of their flowers. 



A. AUo-autogamy. Some individuals are predominantly self- 

 pollinated, others are cross-pollinated. Viola tricolor. 



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