

J 



r 



\ 



1917] 



W I LIE— VA LLISNERIA 



139 



This definite engagement with the surface film does not hinder 

 the free movement of the staminate flowers on the water. In 

 open areas they are caught by every passing breeze and are hurried 

 along the surface of the water. On windy days they go scudding 

 by the observer like tiny flecks of foam. Where the plants grow 

 abundantly they often mass along the windward shores in broad 

 zones of snowy white (fig. 1). 



The anthers dehisce before the flowers open, and the sticky pollen 

 from the pair of stamens of a given flower usually forms a single 

 pollinium (pi. IX). Even if the products of the 2 anthers form 



W** . 



iJ^ 



. 



Fig. 1. — Floating staminate flowers along margin of East Okoboji Lake in north- 

 western Iowa; the dead fish shown near center of picture was about 8 inches long. 



separate pollen masses, these lie so close together as to be prac- 

 tically tangential, and are never widely separated, as shown by 

 Kerner (i). Seen under 



moderate ma 



masses 



;leam like < 

 al in form 



The microspores, which are 



smoo 



adhesi\ 



rubbed 



in holding the spores to the 



ma tic hairs. 



limited 



5 



by the wind, 



spores to the flower, but varying considerably. 



The floating staminate flowers are carried aloi 

 and coming within the radius of the declined surfac 

 pistillate flower slide into the little depression, where they are 



