314 CLEISTOGAMIC FLOWERS. Chap. VIII. 



cells or loculi remarkably distinct; they contain very 

 little pollen in comparison with those of the perfect 

 flowers. 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 membra- 

 nous expansions flatter or not so hoodlike 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 -iftjVfr of an inch in diameter, 

 and therefore of smaller size than the ordinary pollen- 

 grains similarly treated, which have a diameter of 

 WW °^ 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. I 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 an- 

 theriferous stamens. It is remarkable that there is an 

 open passage from the enlarged funnel-shaped extrem- 

 ity 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 considerably 

 from that of the perfect flower; for in the latter it is 

 much longer, and straight with the exception of the 

 rectangular bent stigma ; nor is it perforated by an open 

 passage. 



