168 Lake Maxinkuckee, Physical and Biological Survey 



(Umbra limi}. Dr. Forbes, in 1883, found that forty per cent of 

 the food of this fish was vegetable matter, chiefly Wolffia. 



"Five specimens of the Umbra limi obtained from a pond, cov- 

 ered in September with a film of Wolffia and other vegetation, 

 yielded to the dissector stomach contents consisting of sixty per 

 cent of the Wolffia." 



7. FLORIDA WOLFFIELLA 



WOLFFIELLA FLORIDANA (J. D. Smith) 



This plant is rather common at Norris Inlet among other duck- 

 weeds, but it is much less abundant than most of the others, and on 

 account of its slenderness, and its habit of hiding among other 

 duckweeds, it is not always easy to obtain in quantities. The 

 thalli are very slender, somewhat flattened, attenuate, light-green 

 affairs, sometimes hanging together in quite large stellate masses. 

 It rides deeper in the water than the other duckweeds, and there- 

 fore forms the bottom portion of the layer. Sometimes it grows 

 in thick tangles in the submersed tops of Ceratophyllum. 



Besides being found in the Inlet, it sometimes becomes scattered 

 by south winds to various parts of the shore. A few plants were 

 seen off the springy flat by Overmyer's field. A few near Farrar's 

 pier, and some mixed with Wolffia were observed south of Win- 

 field's. 



Stays green all winter. In 1904 (Dec. 20) bright green plants 

 were noted floating under the ice on the surface of the water. 

 Probably most of the plants sink, to the bottom during the winter, 

 as not many can be seen through the clear ice. This plant, which 

 was very common in 1900 and 1901 is now becoming rare and will 

 probably soon be extinct at the lake. 



8. RICCIA 



RICCIOCAUPUS NATANS (Linnaeus) 



Intermediate between the floating plants and plants growing 

 on shore ; exceedingly similar to the duckweeds during its floating 

 life and behaving much like an ordinary land plant during the other 

 part of its life, is the curious liverwort, Ricciocarpus natans. This 

 plant exhibits in some degree the dimorphism which is generally a 

 well-marked feature of shore-line plants, but which is intensified 

 and reaches its highest expression in woodland ponds. R. natans 

 is predominantly an aquatic plant and is never found where the 

 water supply is not permanent. It is a thin heart-shaped form 

 with prominent masses of rhizoids on the under side, often found 



