Bui. 675, U. S. Dept. of Agriculture. 



Plate I. 



o o o =L 



^ °<< K 

 if .| 



alga 



O o 



OS* 



.5"-"0 ? 

 in o e O 



£ ? c -c 



pel; 



sag 5 



.gogg 

 gggeS 



*1 I 



o^S 



o ,„ ca w 



S ° m c w 

 .5 o © c 5 



o 2 go f- 



= 2-2 



