Feb. 16, 1914 
Indicator Significance of Vegetation 
387 
association, Atriplex canescens , Grayia spinosa , Sarcobatus vermictdatus, 
and Purshia iridentaia , are relatively infrequent. The predominance 
of woody plants distinguishes the sand-hill association of Tooele Valley 
from the corresponding type of vegetation in the Great Plains east of the 
Rocky Mountains. 1 
Next to the shrubs, perennial herbs are the most important members 
of this association. Noteworthy among these are two characteristic 
sand-loving species, Psoralea lanceolata and Abronia salsa. Certain 
bunch grasses, Eriocoma cuspidata , Stipa comata , and Agropyron spica - 
turn, are also important constituents of this vegetation. A few annual 
and biennial species are to be seen during the first weeks of summer, but 
the plants are too small and too short lived to greatly influence the 
appearance of the vegetation. 
The following list includes the more important species noted as occur¬ 
ring in the sand-hill mixed association: 
PERENNIAL species 
Juniperus utahensis (Englm.) Lemm. 
Agropyron spicatum (Pursh) Rydb. 
Eriocoma cuspidata Nutt. 
Stipa comata Trin. and Rupr. 
Eriogonum ovalifolium Nutt. 
Eriogonum kearneyi Tidestrom 
Atriplex canescens (Pursh) James 
Eurotia lanata (Pursh) Moq. 
Grayia spinosa (Hook.) Moq. 
Sarcobatus vermiculatus (Hook.) Torr. 
Abronia salsa Rydb. 
Purshia tridentata (Pursh) DC. 
Psoralea lanceolata Pursh 
Gilia pungens (Torr.) Benth. 
Lap pula occidentals (Wats.) Greene 
Castilleja linariaefolia Benth. 
Artemisia tridentata Nutt. 
Chrysothamnus nauseosus albicaulis (Nutt.) 
Rydb. 
Chrysothamnus pumilus Nutt. 
Layia glandulosa H. and H. 
Senecio uintahensis A. Nels. 
ANNUAL AND BIENNIAL SPECIES 
Abronia cycloptera Gray 
Eriogonum cernuum Nutt. 
Lepidium pubecarpum A. Nels. 
Erodium cicutarium I/Her. 
Gilia leptomeria Gray 
Crytanthe sp. 
Lap pula sp. 
Physical Conditions Indicated 
The soil is nearly pure sand and is easily moved by the wind. The con¬ 
ditions for penetration of the total rainfall are excellent and the run-off 
is negligible. The great depth of loose soil is favorable to storage of 
water during a long period after rains. Only one soil boring in this asso¬ 
ciation was made (June 3), but the location was apparently in all re¬ 
spects a typical one and the resulting data (Table VII) probably repre¬ 
sent the average conditions of moisture and salt content of the soil where 
this type of vegetation occurs. 
1 Shantz, H. L-, Natural vegetation as an indicator of the capabilities of land for crop production in the 
Great Plains area, U. S. Dept. Agr., Bur. Plant Indus. Bui. 201, p. 58-60. 1911. 
