292 



The Ohio Naturalist. 



[Vol. V, No. 4, 



are more or less supplied with red coloring matter, probably a 

 result of the low temperatures to which they have been exposed. 

 The buds continue to expand and the enclosed stem becomes an 

 active, growing plant. Later it may become attached in the 

 mud by roots from the basal end. 



The bladders are mvich redviced, or almost entirely absent 

 from the stems bearing the hibernacula, while they are found 

 within the buds in an immature stage. The spaces between the 

 leaves that go to form the hibernacula, contain various algae, such 

 as Oscillatorias, Desmids, Diatoms and other unicellular forms. 



Fig. 1. Two hibernacula of Utricularia vulgaris on a single stem. 



Fig. 2. Longitudinal section through the middle of a hibernaculum of Utricularia 

 vulgaris. 



Fig. .3. Longitudinal section of an immature bladder. 



The hibernacula of the Potamogetons, the Myriophylkxms 

 and Philotria canadensis, are usually more elongated and the 

 leaves less crowded than those of Utricularia. The buds do not 

 rise to the surface of the water in the spring but remain in the 

 mud and develop roots and leafy shoots which grow tipward 

 toward the surface of the water. 



The Lemnas, Wolffias and Spirodela produce pocket shaped 

 buds, which contain the next years' stem, and like those of 

 Utricularia, usually sink to the bottom of the water on the 

 approach of winter and in the spring rise again to the surface 

 and develop into floating plants. 



