I20 Flowers and their Unbidden Gtiests. 



by the length and narrowness of the passages by which 

 alone it can be approached. This " revolver " forma- 

 tion is specially observable in sundry Gentianese, as also 

 in many species of Convolvulus {C. simlus, G. tricolor, 

 C. arvensis, C. sepium, etc.). The plant, however, 

 which I have selected for illustration is Aphyllcmthes 

 monspeliensis (Plate II. fig. 55, transverse section of 

 upper part of flower). Here the six stout broad filaments 

 are internally in close apposition to the central style, 

 while externally they are adherent to ridge-like 

 processes given off from the mid-rib of each of the six 

 free but overlapping petals. I have also given draw- 

 ings from another plant, Oentianu f/rma Neilr. var. 

 (Plate II. fig. 61), to illustrate the same kind of 

 formation. Here there are five dilated filaments, 

 closely apposed to the five sides of the central 

 ovary. The petals cohere so as to form a tubular 

 corolla, but at the points of coherence their commis- 

 sures form ridges, which project internally and are 

 adherent to the fiOlaments. Similar arrangements, 

 though without the same regularity and elegance, 

 are also common in Caryophyllacese and Cruciferse ; 

 for in many plants from these orders the long thin claws 

 of the petals, together with the filaments, so completely 

 fill up the space between the ovary and the firm upright 

 closely approximated sepals, that only very narrow 

 passages are left, which though they lead to the nectar 

 are yet quite impenetrable by unbidden guests. 



