270 



MR. A. W- BENNETT ON CLEISTOGAMIC FLOWERS. 



detect, entirely suppressed. The ovary is large and conical, and 

 is surmounted by a style and stigma which at once attract atten- 

 tion. The form of these organs in the perfect flowers of this 

 section of Viola (I have had no opportunity of observing them in 

 this particular species) are, as is well known, as follows : — The 

 elongated style rises on the summit of the ovary from a very 

 narrow base, gradually thickening upwards, and bearing the 

 stigma, in appearance remarkably like the beak of a bird, the 

 actual stigmatic surface being a minute cavity (b) on the upper side 

 of this beak near its extremity (fig. 1). In the cleistogamic 



Kg. 1. 



Fig. 2. 



I 



Viola odorata. 1. Stamens and pistil of perfect flower ; b, stigmatic cavity. 

 *~ ' 2. Perfect stamen. 



flowers the style is very short, and curved over in a semicircle, 

 the flat stigmatic surf ace,which faces downwards, being perforated 

 by a funnel-shaped cavity, as shown in figs. 3, 4, and 5. The 

 stamens present as great a divergence. Instead of the five sessile 

 anthers, each consisting of two closely approximate anther-lobes 



Fig. 3. 



Fig. 4. 



Fig. 5. 



I 



Vjpla cucullata. 3. Pistil of cleistogamic flower. 4. Section of same, showing 

 perforation through the style*. 5. Front ^iew of the stigmatic cavity. 



opening by longitudinal slits, and surmounted by a membranous 



In order to make the drawing clearer, the channel through the style is mado 

 considerably wider than it is in nature. 



