CuAp. VIII. VIOLA. 315 



<lowers. The connective expands into a membranous 

 hood-like shield which projects above the anther-cells. 

 These two lower stamens have no vestige of the curious 

 appendages which secrete nectar in the perfect flowers. 

 The three other stamens are destitute of anthers and 

 have broader filaments, with their terminal membran- 

 ous expansions flatter or not so hood-like as those of 

 the two antheriferous stamens. The pollen-grains have 

 remarkably thin transparent coats; when exposed to 

 the air they shrivel up quickly ; when placed in water 

 they swell, and are then f f-J-^ of an inch in diameter, 

 and therefore of smaller size than the ordinary pollen- 

 grains similarly treated, which have a diameter of 

 '^^V of an inch. In the cleistogamic flowers, the 

 pollen-grains, as far as I could see, never naturally fall 

 out of the anther-cells, but emit their tubes through a 

 pore at the upper end. 1 was able to trace the tubes 

 from the grains some way down the stigma. The pistil 

 is very short, with the style hooked, so that its ex- 

 tremity, which is a little enlarged or funnel-shaped 

 and represents the stigma, is directed downwards, 

 being covered by the two membranous expansions of 

 the antheriferous stamens. 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 from one 

 end to the other : a similar passage was observed by 

 Michalet in V. alba. The pistil therefore differs con- 

 siderably from that of the perfect flower ; for in the 

 latter it is much longer, and straight with the excep- 

 tion of the rectangularly bent stigma ; nor is it per- 

 forated by an open passage. 



The ordinary or perfect flowers have been said by 

 gome authors never to produce capsules ; but this is an 



