FLOWERING PLANTS AND FERNS OF INDIANA. 671 



LEMNACE^E. Duckweed Family. 



SPIRODELA Schleid. 



S. polyrhiza (L.) Schleid. Greater Duckweed. 



Commonly found throughout the State in streams and shallow 

 lakes. Very abundant in the pools of the low bottom lands about 

 lakes. 



No specimens in flower have been sent me, nor have I collected 

 the species in flower. 



Tippecanoe (Cunningham) ; Vermillion (Wright) ; Putnam (Mac- 

 Dougal); Hamilton and Marion (Wilson); Fayette (Hessler) ; Vigo 

 (Blatchley) ; Steuben (Bradner) ; Cass (Hessler). 



LEMNA L. 



L. trisulca L. Ivy-leaved Duckweed. Star Duckweed. 



In shallow pools about lakes, in ditches and sluggish streams 

 throughout the State. Frequent, but ordinarily not abundant. 



Flowers as early as May in the southern part of the State and 

 continues until in August. 



Hamilton (Wilson) ; Vigo (Blatchley) ; Steuben (Bradner) ; 

 Kosciusko and Gibson. 



L. minor L. Lesser Duckweed. 



Quite abundant in shallow ponds and lakes and in sluggish streams 

 in all parts of the State. In our area it apparently is most abun- 

 dant in pools protected from long-continued, direct light. 



Flowers from May until September. 



Vigo (Blatchley) ; Noble (Van Gorder) ; Kosciusko and Tippe- 

 canoe. 



WOLFFIA Horkel. 



W. Columbiana Karst. 



Abundant in stagnant pools, about lakes and in shallow ponds 

 throughout the State. This species, as minute alga like grains, floats 

 just beneath the surface of the water. 



Flowers in June and July. 



Vigo (Blatchley) ; Hamilton (Wilson) ; Steuben (Bradner) ; 

 Kosciusko (Coulter). 



