258 Lake Maxinkuckee, Physical and Biological Survey 



176. MINUTE DUCKWEED 



LEMNA PERPUSILLA Torr. 



One of the smallest of the Lemnas; abundant in Norris Inlet, 

 intermixed with Wolffiella floridana; some collected there Novem- 

 ber 18, 1904. 



177. LESSER DUCKWEED 



LEMNA MINOR L. 



Not particularly common in the lake. Most of the plants are 

 found in the great mass of duckweeds near Norris Inlet, the 

 plants of L. minor scattered more or less among the Spirodela. It 

 was also found near Farrar's and at Overmyer's springy flat. In 

 1906 it was quite common in the Inlet, back among the weeds. 

 Along the Kankakee marshes almost pure growths of this plant 

 cover great areas with an almost unbroken scum. 



Found abundantly in blossom by Norris Inlet, June 13, 1901. 

 The blossoms are minute white specks like bits of dust. 



178. COLUMBIA WOLFFIA 



WOLFFIA COLUMBIANA Karst. 



Not particularly abundant at the lake. There is, indeed, a con- 

 siderable amount down by Norris Inlet, but it is so intermixed 

 with other duckweeds, which are more conspicuous and abundant, 

 that it does not make much of a show. At Eagle Lake, Kosciusko 

 County, and at Twin Lakes, it covers the entire water surface near 

 shore for a considerable area, making an almost unbroken scum. 

 This is one of the most minute of flowering plants, the entire plant 

 being not much larger than a pin-head. It was noticed in blossom 

 several times. On October 9, 1900, the plants were in blossom quite 

 freely. We got a tubful in which many were in bloom. They 

 were found in flower also on October 24 of the same year. At 

 Put-in-Bay, Lake Erie, some were noted in blossom about the 19th 

 of July. The flowers appear like minute white dust specks. 



According to Forbes* Wolffia is not unimportant as a food sup- 

 ply for certain species of fishes, forming in some cases 95% of 

 the stomach contents of the Buffalo-fish, Ictiobus bubalus, 8% of 

 the food of the carp sucker, Carpiodes carpio, and the larger por- 

 tion of the food of the mud-minnow, Umbra limi. 



Plants occasionally drift among the bulrushes along shore at 

 various parts of the lake, as near Winfleld's, where they hold their 

 own for some time in the shelter of the rushes, but they do not ap- 

 pear to increase much. 



* Nat. Hist. Surv. 111., Ill, Ichthyology. 



