PAPERS ON BOTANY 
: merged into one, and we find the vegetation well on its way 
toward the re-establishment of the bottom-land forest (Fig. 
3). The trees consist of the willow, Salix nigra, which was 
probably the first to appear; the cottonwood, Populus deltoides, 
which occurs up to eight inches in diameter; soft maple, Acer 
saccharinum; red elm, Ulmus fulva, and sycamore, Platanus 
occidentalis, the last three all being small. The undergrowth — 
is such as would be expected in such a situation and need not 
be described here. 
As previously stated eighteen years have elapsed since this 
eastern section was abandoned by the mining company. Since _ 
numerous small individuals of the sycamore, one of the very 
characteristic bottomland trees, are already present it is prob- — 
able that twenty-five or thirty years will be sufficient for the — 
complete re-establishment of the typical bottomland forest. 
ON THE FOLIAR TRANSPIRING POWER OF TILIA 
J. EK. Crises, Cottece or Emporia, KAN. 
ABSTRACT 
Studies on the foliar transpiring power of Tilia were con- 
ducted during the summer of 1916 and 1917 in the dune area 
of northern Indiana. Tilia was chosen because of its unusual 
ability to surmount the dunes which move upon and cover large 
areas of mesophytic forest. In fact it is the only tree represent- 
ative of the forest which displays this ability to any degree. 
Five stations were selected which represented gradations in 
habitat; Station A. was located in a forested dune area which 
had become completely stabilized and contained an abundance 
of herbaceous undergrowth and considerable humus. Station 
B. was chosen at a point near the edge of the forested dune and 
was partly exposed to the wind. Station C. was at the very © 
edge of the forest and was also located at the edge of a blowout 
where the humus had been largely removed. Station D. was on 
the lee side of an advancing dune where the exposure, especially 
to the sun, was very great, and where there was no humus. 
Station E. was situated at the top of a high dune which was 
