132 Shazv — Structure of the Floivcrs in 



reverse of what Darwin and other observers have found in 

 other cleistogamic flowers. 



Gynoecium. — ^A. In the chasmogamic flowers the exter- 

 nal appearance is shown in Plate XVII, Fig. i. The style 

 curiously enough bears two different structures, either of 

 which might be taken for a stigma. Terminally situated is a 

 tuft of hairs amongst which microspores are found, often in a 

 germinating state. Laterally is a glandular knob where the 

 microspores also stick and germinate. Each of these repre- 

 sents the tip of a cai-pel, but only the latter is functional as a 

 stigma. As the flower opens an abundant secretion is poured 

 forth from the glandular stigmatic knob. The terminal hairy 

 tuft is close to the anthers under the hood. It would seem 

 that the microspores might be caught in this tuft and remain, 

 where they may stick to an insect, leaving the flower after 

 having been smeared with the stigmatic secretion while seek- 

 ing nectar in the base of the ovary. 



A most interesting feature is that in at least many individuals 

 a canal traverses the style, and forms an open passage from 

 the ovarian cavity to the exterior. The stalk of the hairy tuft 

 is a deeply channeled structure, and this channel is continued 

 into a canal in the style proper which below divides into two 

 passages, leading into each cavity of the ovary. These last 

 passages are often nearly choked up with hairy processes 

 from the surrounding tissue. Whether the whole canal can 

 have any function is hard to conjecture, but it suggests the 

 condition seen in the Resedaceae. Darwin ^ found a similar 

 condition in the cleistogamic flowers of Viola canina and 

 Viola alba. Of the cleistogamic flower of Viola caiiiiia he 

 says : " It is remarkable that there is an open passage from 

 the enlarged funnel-shaped extremity to within the ovarium ; 

 this was evident, as slight pressure caused a bubble of air 

 which had been drawn in by some accident, to travel freely 



•Forms of Flowers, p. 315. 



