Mar. 22, 1924 
Tissue Fluids of Indicator Plants 
921 
predecessors. Those concerning crop production represent their obser¬ 
vations as well as our own. 
Eight major divisions of the vegetation have been recognized: The 
Stansbury Mountains at higher altitudes, the sagebrush association, the 
sand-hill mixed association, the Kochia association, the shadscale asso¬ 
ciation, the greasewood-shadscale association, the grass-flat communities, 
and the salt-flat communities. 
With the exception of the Stansbury Mountains at higher altitudes, 
and to a less extent of the grass-flat and the salt-flat communities, these 
associations are distinguished primarily by their woody plant species. 
The herbaceous plants are largely ephemeral, completing their growth 
during the early spring, while moisture is still available near the surface 
and while the salts have been to some extent washed out of the super¬ 
ficial layers of soil. These ephemeral species are to some extent common 
to all the associations. Because of their general distribution, as well as 
because of the limited period during which they may be identified, they 
are of less value as indicator plants than the woody species which are 
active throughout the season. The following generalizations are, there¬ 
fore, based upon the results for ligneous species. 
The sagebrush {Artemisia tridentata) association, which occupies the 
land nearest the mountains and is the highest which is of interest for ag¬ 
ricultural (as distinguished from grazing) operations, occurs generally 
on rather deep soil, of rather light texture, easily permeable to water, 
and free from large quantities of salts. With the exception of the Stans¬ 
bury Mountains at higher altitudes and possibly of the sand-hill mixed 
association, the plants of the sagebrush association have the lowest 
osmotic concentration, specific electrical conductivity and chlorid con¬ 
tent of any of the associations investigated. The average values of these 
constants are about 22 atmospheres osmotic concentration, 0.024 mho 
conductivity and 2.65 gm. per liter chlorid content. These values are 
of about the same order as those found near the end of the season in 
small grains as grown under dry farm agriculture at Nephi, Utah. 8 The 
sagebrush land is the locus of the chief dry farming operations of the 
region. 
The Kochia {Kochia vestita) association which occupies areas lying 
below the sagebrilsh zone, is found on land of finer texture, relatively 
greater impermeability to water, higher moisture-holding capacity, and 
greater salt content at a small depth below the surface. Sufficient 
moisture for growth is generally wanting during the summer. Dry 
farming is precarious, owing to the small depth of soil free from salts. 
Even under irrigation the relatively impervious nature of the soil might 
make difficult the washing out of the salts to a depth which would permit 
profitable crop production. The vegetation is characterized by a higher 
osmotic concentration, specific electrical conductivity and chlorid con¬ 
tent than that of the sagebrush association. When the sagebrush pene¬ 
trates into the Kochia association it is extremely dwarfed, and its tissue 
fluids may attain an abnormally high osmotic concentration. 
The shadscale {A triplex confertifolia) association occupies the outwash 
slopes below the Kochia association. The soil is similar, in the main, to 
that of the Kochia association, but frequently contains much gravel and 
may become even drier during the summer. Dry farming is hazardous, 
but where water is available for washing out the salt and supplying 
8 Statement based on unpublished results. 
