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2f0 FAMILIES OF FLOWERING PLANTS 
Fic. 207. Another view of the bladderwort ( Utricularia) showing the air bladders 
by which the plant is floated. After Kerner, from Coulter’s ‘‘ Plant Re- 
lations,’’ by courtesy of D. Appleton & Co. 
the south, and the species are found in extreme arctic regions as well; 
they are called butterworts, from the slippery surface of the leaves, 
which are borne in a basal tuft or rosette. 
