346 



MB. II. B. GUPJPY OS PLANT DISPERSAL. 



* 



I found them floating in the Lea and th^ Thames in January, <fcc. 



1 



Lemma trisulca seems to live through the winter in the Lea and 

 Thames. After manj weeks of frost in the winter of 1890-91, 

 I found it in January inclosed in quantity in the ice of an Epping- 

 Forest pond. The fronds of L. gibbet, polyrrhiza, and trisulca 

 behave like those of L. minor both in sea-water and when 

 dried. 



