132 MICHIGAN ACADEMY OF SCIENCE. 



was sometimes perfoliate near tlie margin, but notched at the base, and 

 sometimes the petiole was attached as usual, and the base was heart- 

 shaped. The fourth leaf was always perfoliate, as were the succeeding 

 ones, the insertion of the petiole approaching nearer the center of the 

 oval leaf in each successive form, but in none of the seedlings studied 

 did the type form of a perfectly elliptical leaf with the petiole in the 

 center, appear. 



NOTES ON UTRICULARIA RESUPINATA B. D. Greene. 



BY CHARLES A. DAVIS, ALMA. 

 [Abstract.] 



This plant grows in the sand along shallow margins of lakes. It has 

 been found in Pine Lake^ Ingham county; Woodward Lake, Ionia county; 

 Bass Lake, Montcalm county, and one or two other localities in the 

 state. It is often overlooked because of its resemblance to small grass- 

 like submerged plants, only the tips of the linear leaves appearing above 

 the sand. The characteristic bladders are attached to the bases of tht 

 leaves, and to special branches of the stem. The leaves in floating- 

 specimens are in whorls of three. Two of these are geotropic, and one 

 heliotropic, all bear one or more bladders. The geotropic leaves are 

 rather smaller than the others. The growing tip of the stem is also 

 slightly geotropic, but apparently not decidedly so. In plants growing 

 under natural conditions the stem grows a short distance below the 

 surface of the sand, the base of the upright leaf being buried perhaps an 

 inch. The two geotropic leaves then spread out widely in the sand 

 and sometimes bear several bladders. There are also special branches 

 at irregular intervals which seem to bear only bladders without any true 

 leaves. Th.ese seem more numerous in the vicinity of the base of the 

 flower stalk. There are also fine branches of the stem which seem 

 to be roots, but it seems probable that they are bladder bearing branches 

 from which the bladders had been broken in the process of collecting. No 

 roots appeared on floating stems kept for two years in an aquarium. The 

 stems survive the winter buried in the sand. 



TREES AS DWELLING PLACES FOR ANIMALS. 



BY W. J. BEAL. 



The rodents and the woodpeckers seem to be especially adapted to 

 living in trees, as the former have stout chisel teeth and the latter a 

 beak for pecking lioles. 



The chief point I had in mind, when I decided to speak on this topic was 

 to show how these holes originated and how they were kept in good con- 

 dition suitable for dwellings. If you were to hunt about in the forests, 

 you would be surprised to discover the great number of kinds of injuries 

 that trees are subject to. The holes in trees were not purposely left 



