490 
WALTER L. C. MUENSCHER 
would warrant us in drawing the conclusion which he makes in regard 
to the relation of the amount of transpiration from rooted plants and 
detached cuttings of plants. 
In order to satisfy myself as to the possibility of a relationship 
between the amount of water lost from plants with their roots and 
plant-parts without roots, an experiment was conducted with five 
cultures of cuttings in water and ten cultures of rooted plants in jars 
for each of eight species. 
The two sets of jars were run simultaneously for 24 hours from 
6 o'clock P. M. January 4, to 6 o'clock P. M. January 5, 1915. The 
results of the experiment are given in the form of curves in figure I. 
The two curves show that the water loss in cuttings is about 20 or 30 
percent less than the amount lost by the same plant under similar 
conditions when rooted in a jar. In every case the amount of transpir- 
ation was less per unit of leaf surface from cuttings than from rooted 
plants. The cuttings consisted of short stems with from two to five 
leaves and were removed from the plants under water. The quantity 
of transpiration is recorded in milligrams per hour per square deci- 
meter of leaf surface. 
In brief, the method employed in the following experiment con- 
sisted in sealing jars so as to prevent all loss of water except that which 
is lost through the plant; determining this loss by weighing; and then 
computing the amount of loss per unit of leaf area and stomatal 
aperture. 
I . Selection and Preparation of Plants 
In selecting the species used in this experiment several important 
considerations had to be kept in mind. Only plants with simple 
stomata were taken; that is, plants with stomatal elaborations such 
as pits, plugs, many hairs or extremely sunken stomata could not be 
used in this work so as to bring us face to face with the one factor, 
namely, the relation of the size and number of stomata to the amount 
of water lost. 
The species had to be chosen so as to present the widest possible 
range in size of stomata. Only those plants^ could be selected which 
could be readily grown under greenhouse conditions such as those 
under which the experiment was performed: lilacs and cottonwoods 
were started, but shed their leaves and failed to send out a new 
set of normal leaves; plants of Datura stramonium were started 
