Feb. i6,i 9 i4 Indicator Significance of Vegetation 411 
Several of these samples—e. g., Nos. 76 and 97—were taken at places 
where Allenrolfea grew in company with Sarcobatus and where the salt 
content and moisture content of the soil were lower than in the typical 
Allenrolfea community. It is clear, nevertheless, that the presence of 
this plant is an almost invariable indicator that the soil (1) contains 
moisture available for growth, at least below the surface foot, throughout 
the summer; and (2) is excessively saline to a depth of at least 4 feet. 
Salicornia Utahensis Community 
Appearance) and Botanical Composition. —Salicornia utahensis 1 
(PI. XLVIII, fig. 2) is a nearly leafless plant with fleshy, jointed stems. 
It resembles small plants of Allenrolfea, but is readily distinguished by 
the light blue-green color and by the fact that the branches are opposite, 
while in Allenrolfea they are alternate. It spreads by creeping rootstocks 
and forms pure colonies of greater or less size which sometimes cover the 
bottoms of depressions (see right end of PL XLITI, fig. 1), sometimes 
occupy hummocks elevated but a few inches above the general surface of 
the flats. In this case the appearance is much like the Allenrolfea hum¬ 
mocks (PL XLVIII, fig. 1), except that the latter are higher and the 
plants are larger and darker colored. This Salicornia is also found in 
association with Allenrolfea and with Distichlis. 
Physical Conditions Indicated.—No determinations were made of 
the moisture equivalent and moisture content of the soil where this 
community occurs, but two borings carried to a depth of 30 inches and 12 
inches, respectively, showed that abundant moisture was present through¬ 
out that depth, as would be expected from the slight elevation of the 
land above the water surface of the lake. The salt contents of different 
depths of the soil from the borings in question are given in Table XVII. 
Table XVII .—Salt content of soil in the Salicornia utahensis community. 
Depth of 
soil. 
Salt content. 
Sample No. 1. 
Sample No. 2. 
Inches. 
0 to 6 
7 to 12 
0 to 12 
13 to 18 
18 to 30 
Per cent. 
2 . 20 
> 2 - S° 
Per cent. 
>2. 50 
2. 25 
>2. 50 
2 . 20 
Salicornia Rubra Community 
This small, shallow-rooted annual species of Salicornia is found most 
abundantly in pure communities along drainage channels in the salt flats. 
The patches of Salicornia rubra are very conspicuous late in the summer, 
1 This species was recently described from specimens collected by the writers in Tooele Valley by Mr. 
Ivar Tidestrom. (A new Salicornia. Proc. Biol. Soc. Wash,, v. 26, p. 13, 1913.) 
