84 
other soil factors they are comparatively indifferent. Too much 
sun, however, or too much moisture kills them very readily. 
They are to be found, therefore, on the forest floor and less 
abundantly about the shaded edges of the forest. They do not 
appear to be able to compete with grass or other tightly growing 
herbaceous plants but piece a clean floor. They grow very 
readily on rotting woods. 
. e, 1906, eee William J. Gies, Consulting Chemist 
to the Botanical Gardens, suggested that the series of experi- 
ments described in this paper be undertaken to determine whether 
any chemical constituent’ of the soil in the hemlock grove was 
the detrimental factor causing the failure of the hemlock seed- 
lings to develop. 
Areas shaded by three or four trees each, were marked out 
and the number of hemlock seedlings that germinated that spring 
were counted. The number varied from thirteen or fourteen 
under trees in the interior of the grove, to from sixty to seventy- 
five under trees near the margin. In an open space of equal area 
where ash saplings four feet high, red-berried elder, viburnum, and 
sear ea aa such as sweet cicely were found, nearly one 
ndred w noted. One month later only about a fourth of 
Sella remained, and at the end of three months only 
thirteen seedlings survived in the entire area shaded by hemlocks, 
while the number beneath the deciduous trees and shrubs nearly 
aide that of the first count observed. 
ne 29, 1906, about one half bushel of surface soil was taken 
eA the hemlock woods near the Lorillard mansion and the 
same amount from the grove of deciduous trees adjacent. There 
were no evidences of the work of earthworms or chipmunks under 
the hemlocks but there were signs of both under the deciduous 
trees, In contrast with the bareness of the soil beneath the hem- 
under the deciduous trees, including dogwood, sassafras, violets, 
jack-in-the-pulpit, ashes, viburnums, and young hemlocks. 
Soil from each of these localities was ground in a mortar on 
four successive days and allowed to dry in the intervals. Then 
a part of each was sifted through sieves and cheese-cloth, and 
