REPROD UCTION. 217 



surround the ovary. Such a flower is said to be perigynous. 

 The floral axis is also depressed, but the ovary differs from case 

 2 in that it is " free. ' ' In the case of epigyny , according to 

 GOBEL'S investigations, the cup-shaped floral axis is lined on its 

 inner surface by the basal parts of the floral envelopes. These 



FIG. 137. Epigy nous flower FIG. 138. Perigynous flower (cherry). 



(apple). ('After Berthold and Landois.) 



(After Berthold and Landois.) 



floral envelopes have a strong intercalary growth, soon enveloping 

 the ovary, with the exception of the terminal portions of the styles 

 and stigma. In the perigynous flower the intercalary growth of 

 the cup- shaped axis is perhaps a little below the insertions of the 

 floral coverings, that is, the floral insertions are so near the apex 

 of the torus that they are not affected by the intercalary growth ; 

 hence the torus is not enclosed by the floral coverings. Forms 

 intermediate between epigyny and perigyny are not wanting. 



The individual parts of the flower may be free or united / 

 sometimes the organs are free below and united (by growth) above, 

 as, for example, the stamens of the Composite. The number of 

 floral parts differs greatly in different flowers. For example, the 

 stameniferous flower of Euphorbia has but one stamen, while the 

 flowers of the NympJiaeece, may have more than one hundred. 



The number three prevails in the floral elements of monocoty- 

 ledons. The numbers vary among dicotyledons, though fives are 

 very common. 



According to the arrangement of floral leaves we may recognize 

 the following forms of flowers. 



1. Cyclic flowers: the elements of one kind of floral leaves 



