644 



PHANEROGAMS. 



regard to the relationships here suggested, the flowers becoming diclinous from 

 the stamens in the female flowers developing as sterile staminodes, which may be 

 considered as the first step towards abortion, while in the male flowers the three 

 carpels are replaced by as many fertile stamens (Payer). 



Fig. 452.— Diagram oi Rhus (Anacardiaceae). 



FIG. 453.— Diagram of Crozophora (Euphorbiaceae), a female, 

 b male flower. 



Reference was made in the Introduction to Angiosperms (pp. 601, 610) to the 

 interposition of a whorl of stamens between the members of a previously formed 

 staminal whorl; and it was mentioned that the interposed whorl has sometimes not 



Fig. 454.— Diagram, of pentamerous Ericaceae and Epacridese. 



Fig. 455.— Diagram oi .-Esachis (Hippocastanene). 



the full number of members. These phenomena occur in various large groups of 

 Dicotyledons \ In Fig. 454 the five stamens of the decandrous flower of the group 

 of Bicornes which are interposed as a whorl of full number within the first whorl 



Fig. 456.— Diagram of Primulaceae. 



Fk;. 457.— Diagram of Vitis (Ampelideae). 



are indicated by the lighter colour. The same is the case with the larger number of 

 Gruinales, among which however the Balsaminese possess only the typical five 

 stamens ; the Lineae and the genus Erodium have five additional rudimentary 

 stamens interposed between them ; while in Peganum Harmala and Monsonia the 



^ Payer's figures show that the interposed whorl, although of later origin, is sometimes exterior 

 to the typical whorl. The main point is that the position and number of the other parts of the 

 flower are exactly as if there were no interposed whorl. 



