Feb. 16, 1914 
Indicator Significance of Vegetation 409 
The vegetation of the flats and depressions comprises several commu¬ 
nities, each characterized by the presence of a single species —Allenrolfea 
occidentalism Salicornia utahensis , and *S. rubra. The first of these is by 
far the most abundant and widely distributed. These three species 
appear to be the most salt resistant of the flowering plants of this region, 
taking possession of the land left bare by the recession of the lake as 
soon as its salt content has been reduced sufficiently from the point of 
saturation with the excessively saline lake water to permit the growth of 
any flowering plant. 
Fig. ii .—Allenrolfea occidentals: A, Detail of a fruiting branch, showing the cylindrical, fleshy, practically 
leafless stems; B t a plant showing the large taproot and rather scanty lateral roots characteristic of this 
species. 
Aixenrolfba Community 
Appearance and Botanicae Composition. —The dominant species, 
Allenrolfea occidentalism is a shrubby plant with numerous cylindrical, 
jointed, fleshy, practically leafless branches and a large taproot (fig. 11). 
In Tooele Valley it rarely exceeds a height of 2 feet. There is con¬ 
siderable variation in the habitat of this plant, but it develops most 
characteristically on low hummocks on the salt flats (PI. XI/VIII, fig. 1) 
and near the bases of the higher ridges, usually preferring a slightly 
