80 THE STRUCTURE OF FLOWERS. 



from the calyx, yet its cord is common with that of the latter 

 below. 



The epiphy lions or eplpetalous condition of the stamens is 

 almost invariably associated with a state of cohesion of the 

 perianth-leaves and petals of the corolla ; as exceptional 

 instances are Scilla and Lychnis, which have the parts of the 

 perianth and corolla free, but with the stamens adherent to 

 them ; while, conversely, CampanulacecB and Ericacece have 

 gamopetalous corollas, but the stamens not adherent to 

 them.* 



The rationale is primarily, in many, perhaps in every 

 case, an adaptation to insect agency. In the majority of 

 gamopetalous corollas, the honey usually lies somewhere 

 between the insertion of the corolla and pistil, being secreted 

 by one or more glands or an annular disk round the base of 

 the ovary. There are two positions in which the anthers 

 may be placed in regular gamopetalous flowers with reference 

 to the visits of insects for the honey; either around the tube, 

 as in the Primrose and Scilla, or close around the style, as 

 in Convolvulus, Campanula, and Crocus. In the former case, 

 when an insect passes its head or proboscis down the tube, it 

 touches the anthers on one side of it and the stigma on the 

 other ; but as the proboscis may pass on either side of the pistil 

 in the same and different flowers, that is on the near or 

 remote side, with reference to the position of the insect, such 

 flowers have every facility of being crossed. If they be 

 hcterostyled, as the Primrose, then of course each kind has the 

 greater chance of being crossed by the other sort. 



* The distribution of the coi-ds in the floral receptacle of Azalea, 

 between the insertion of the corolla and pistil, is ve»"y anomalous, having 

 no symmetrical arrangement around the centre ; while the cords of the 

 corolla of Campanula, as described above, are peculiar for other reasons. 

 This may, perhaps, have something to do with the exceptional freedom 

 of the stamens from the corolla. 



