76 



PUBLIC HEALTH BULLETIN NO. 2 86 



3. Limnobium L. C. Rich. 



L. spongia (Bosc) Steud. Frog-bit — Fairly common over most of 

 our territory. It has been noted in very acid and in alkaline waters, 

 thus showing considerable tolerance. It has been found in associa- 

 tion with Anopheles and is mat-forming. 



GRAMINEAE Grass family 



1. Plants floating, or forming mats at surface of water', 2. 



or creeping along ground. 

 1, Plants essentially erect 3. 



2. Leaves floating flat on surface; inflorescences 7. Hydrochloa, p. 82. 



minute and inconspicuous (fig. 1). 

 2. Leaves not flat-floating; inflorescences large 9. Paspalum, p. 82. 



and conspicuous (fig. 2) . 



a/Z 



FlOUBB 1. 



Figure 2. 



