1204 A TEXTBOOK OF THEORETICAL BOTANY 



Fig. 1 174. — Transverse section of a young ovary of Liliiim, 

 formed of three united carpels. The larger vascular 

 bundles mark the dorsum of each carpel, the long dark 

 bundles are the fused marginals marking the lines of 

 division between the carpels. There is a loculus for each 

 carpel containing two rows of o\ules borne on the in- 

 turned carpel margins. 



compound nature. The first case is truly syncarpous, the second is dis- 

 tinguished as paracarpous. Both are included under the term coenocar- 

 pous. 



A limited number of species in certain families show an opposite kind of 

 carpellary union, with free ovaries and with styles and stigmas united. This 

 is to be seen in Asclepiadaceae, where it is a characteristic of the family, 

 in some Apocynaceae, e.g., Vinca, and in some Rutaceae, e.g., Dictamnus, 

 but it is an exceptional condition. 



Apocarpous carpels may be spirally arranged in some of the families 

 where that condition obtains in other parts of the flower, though even in 

 some of these the carpels may be whorled, as they are in the majority of 

 families both with apocarpous and with coenocarpous gynoecia. In the 

 latter the carpels are invariably whorled. 



The number of carpels is very often less than the number of parts in 

 other floral whorls, perhaps because of the limited space available at the 

 summit of the axis. There may often be no more than one, or there may be 

 only one fertile carpel, with obvious traces of the abortion of others, as in 

 Viburnum and Valertanella. Whether this be so or not, the solitary carpel 

 must be regarded in almost every case as derived by reduction from a whorl, 

 though it may only have been from a whorl of two. This brings up the 



