394 
Journal of Agricultural Research 
Vol. I, No. s 
not superior to the Kochia. The line of demarkation between the 
Kochia and shadscale associations is never a sharp one, and this con¬ 
forms with the fact that the physical conditions indicated by the two 
types of vegetation are similar. 
shadscale association 
Topographical Relations 
The shadscale association is one of the most characteristic and important 
of the Great Basin region In the Tooele Valley (see map, PI. XLII) it 
occupies a wide belt across the middle part of the valley, just below the 
Kochia belt, extending farthest northward along the base of the Stans- 
bury Range. The dominant species as a constituent of the greasewood- 
shadscale association extends to the edge of the grass flats and beyond 
that area occupies ridges and hummocks on the salt flats which border 
Great Salt Lake. Isolated small patches of pure shadscale also occur 
within the area mapped as salt flat. 
Botanical Composition 
The most abundant plant of this association is the species of saltbush 
(Atriplex confertifolia) which is commonly known as shadscale, from the 
shape of the scalelike bracts which envelop the fruits. (See fig. 9.) The 
number of associated species is much smaller than in the sagebrush 
association, and those which occur are usually represented by fewer 
individuals. The plants which were noted as occurring in this associa¬ 
tion are the following: 
perennial species 
Poa sandbergii Vasey 
Sitanion minus Smith 
AUium acuminatum Hook. 
Atriplex confertifolia (Torr.) Wats. 
Eurotia lanata (Pursh) Moq. 
Kochia vestita (Wats.) A. Nels. 
Opuntia sp. 
Lappula occidentalis (Wats.) Greene 
Artemisia spinescens Eat. 
Chrysothamnus marianus Rydb. 
Tetradymia glabrata Gray 
Tetradymia spinosa H. and A. 
ANNUAL AND BIENNIAL SPECIES 
Bromus marginatus seminudus Shear 
Lepidium jonesii Rydb. 
Thelypodium elegans Jones 
Cryptanthe multicaulis A. Nels. 
Oreocarya shantzii Tidestrom 
Townsendia watsonii Gray 
Appearance 
The general appearance of the shadscale association (PI. XLVII, fig. 1) 
is due almost entirely to the dominant species. Atriplex confertifolia as 
found in Tooele Valley is a rounded bush, usually about 18 inches in 
height and also in diameter, with rigid, spiny branches and harsh dry¬ 
looking foliage. (See fig. 9.) The individual plants tend to form low 
hummocks, the soil immediately about them being held by the partly 
