896 
Journal of A gricultural Research voi. xxvn, no. 12 
and the shadscale associations, in the localities where springs occur along 
the margins of the salt flats, and in the small islands of Kochia in the 
sagebrush association. Such localities give the opportunity of investi¬ 
gating in close association pairs of species which are normally different 
in their distribution. It has been necessary to explain certain of these 
•cases, and this has laid wholly undue emphasis on the indefinite nature 
of the transitions, which in general are quite as sharp and definite as 
our predecessors have indicated. 
Another factor tending to produce an apparent difference in the results 
of the two studies of the region lies in the fact that in seeking for materials 
for physiological determinations the writers availed themselves of tissues 
of a single plant, or of but a few individuals of the rarer species. These 
would be practically left out of account by the descriptive ecologist in 
mapping the vegetation. Thus from the descriptions and species lists 
of the writers it might appear that Kearney and his associates over¬ 
emphasized the small number of the dominant species. This is not at 
air the case. 
STANSBURY MOUNTAINS AT HIGHER ALTITUDES 
The highest zone of Tooele Valley which is of agricultural (distin¬ 
guished from grazing and water conservation) interest is that formed 
by the great alluvial cones or fans (outwash slopes). These are, or 
have in all probability been in times past, largely covered by the sage¬ 
brush association. 
While Kearney and his party carried their observations no higher 
than the sagebrush association of these broad slopes which border the 
steeper foothills, it has seemed desirable in a consideration of the tissue 
fluids of the plants of the region, to include a few determinations made 
at higher altitudes in the Stansbury Mountains. These may serve as a 
basis of comparison with those taken in the desert valley. 
The species mentioned give some idea of the associations to which the 
plants belong. A detailed discussion of the habitats is omitted, since 
we understand that Dr. C. F. Korstian, who has given much attention'* 
to the Wasatch Mountains, will treat the problem of the tissue fluids of 
the plant associations of these mountains in considerable detail. 
The constants for the species of this association appear in Table I. 
Table I. —Physicochemical constants for species of the Stansbury Mountains at higher 
altitudes 
Growth form and species. 
Date. 
Freezing 
point 
depres¬ 
sion, 
A. 
Atmo¬ 
spheres 
osmotic 
concen¬ 
tration, 
P. 
Specific 
electrical 
conduc¬ 
tivity, 
K. 
Ratio, 
conduc¬ 
tivity to 
depres¬ 
sion, 
K/A. 
Chlo- 
rids 
per 
liter, 
Cl. 
TREES 
1920. 
Pinus flexilis James. 
July 23 
I.44 
17-3 
0.0086 
O.OO 59 
0.4 
Pseudotsuga mucronata (Raf.)Sudw. 
June 21 
1.85 
22.3 
.0087 
.0047 
0.7 
July 23 
i-5o 
18.0 
.0081 
.0054 
Average. 
1.68 
20.2 
.0084 
.0050 
0.7 
Populus aurea Tidest. 
June 21 
i -54 
18.5 
•0137 
.0089 
o-3 
July 23 
1.81 
21.8 
.0099 
•0055 
0.2 
Average. 
1.68 
20.2 
.0118 
.0072 
o-3 
