380 Cooke and Schively on Observations on the 



In the cleistogamic flower, the filament shows the same 

 structure as the evident one, but it is much smaller. The 

 hairs developed on its lower portion are greatly reduced both 

 in number and in size. The anther lobes are very much 

 smaller also, but differ scarcely at all in structure. The only 

 noticeable difference is in the greatly reduced development 

 of hairs on these lobes. None at all are present on the upper 

 and lateral surfaces ; a few are scattered about on the lower 

 surface. 



The great reduction in the development of hairs within 

 the cleistogamic corolla is probably due to the fact that defi- 

 nite insects are excluded, and no provision has to be made 

 to ensure their aid in fertilizing the ovules. 



There is no observable difference between the pollen 

 grains of the two flowers. And although the anther cavi- 

 ties are much larger in the evident flowers, yet the grains 

 lie much nearer together in the cleistogamic stamens. By 

 actual counting of the numbers of pollen grains found in 

 many sections of anther cavities in both kinds of flowers, it 

 was found that the average number was greater in the case 

 of the cleistogamic flower. 



The Pistil. — The structure of the pistil is nearly identical 

 in the two flowers, though the styles differ greatly in length 

 (Figs. 3 and 4). 



The ovary is more narrow and high in the chasmogamic 

 flower, and is shorter and broader in the cleistogamic one. 

 Otherwise the following description applies to both. The 

 ovary is superior, one-celled, with four parietal placentas run- 

 ning vertically through its walls, and projecting inward from 

 them. Each placenta is traversed by three bundles, a large 

 central one and a smaller one on each side. There are usu- 

 ally five bundles rising in the ovarian wall, there being one 

 behind each placenta always. A definite epidermis of small 

 regular cells lines the cavity of the ovary. It passes out con- 

 tinuously along the funiculi, where the ovules are given off, 

 so that the placentar and funicular tissue are directly con- 

 tinuous. 



