May 24, 1924 
Significance of the Southwestern Desert Vegetation 749 
Less Frequent or Rare 
Atriplex fasciculata S. Wats. 
Evax multicaulis DC. 
Calyptridium monandrum Nutt. 
Cryptanthe sp. 
Dr aba cuneifolia Nutt. 
Erodium texanum A. Gray. 
Erodium dcutarium (L.) L’H6r. 
Gilia floccosa A. Gray. 
Gilia inconspicua (J. E. Smith) Dougl. 
Sphaeralcea sp. 
Melilotus indica (L.) All. 
Mentzelia albicaulis Dougl. 
Monolepis nuttalliana (Schult.) Greene. 
Plantago fastigiata Morris. 
Nemoseris neomexicana (A. Gray) 
Greene. 
Senecio sp. 
Sonchus asper (L.) Hill. 
Sophia glabra Woot. & Standi. 
Spermolepis echinatus (Nutt.) Heller. 
Microseris linearifolia (DC.) A. Gray. 
Lappula occidentals (S. Wats.) Greene. 
ANNUAL AND BI10NNIAL SPECIES OF THE DESERT-SAGE ASSOCIATION IN THE 
COACHELLA VALLEY 
Common or Frequent 
Plantago erecta Morris. Sphaerostigma veitchianum (Hook.) 
Eremalche exilis (A. Gray) Greene. Small. 
Dipetalia subulata (Webb & Berth.) Conanthus demissus (A. Gray) Heller. 
Kuntze. Amsinckia menziesii (Lehm.) Nels. & 
Sophia pinnata (Walt.) Howell. Macbr. 
Mentzelia albicaulis Dougl. 
Less Frequent or Rare 
Palafoxia linearis Lag. Pectis papposa Harv. & Gray. 
APPEARANCE 
The gray of the desert-sage sets it off sharply from the creosote bush association 
even at considerable distances. A typical area shows a uniform shrubby growth 
(PI. 6, B), about 3 feet high, the plants growing in clumps a few feet apart, but 
not nearly so widely spaced as the creosote bush. Mesquite trees are often 
scattered throughout this uniform growth of desert-sage. Each of the clumps 
is on a low hummock built up by soil that has been blown in around the bushes. 
The desert-sage is much smaller than the creosote bush and forms a dense rather 
than an open bush. There are several main branches coming up from the ground 
(PL 7, B) that are very crooked and very much branched at the top. In spring 
there is a dense covering of small grayish leaves on the new shoots. In fall 
most of the leaves have fallen off but there are large quantities of fruits. 
PHYSICAL CONDITIONS INDICATED 
Soil Moisture 
The type of soil covered by the desert-sage is almost a fine sandy loam (Tables 
X and XII). The moisture-holding capacity is therefore much greater than 
in the case of creosote bush. Due to the flood waters in Coachella Valley the 
surface of the soil is crusted with a layer of silt that is not easily penetrated by 
the water. This intermittent depositing of silt leads to a lack of uniformity 
of the subsoil, and there are often alternating layers of sand and silt in the third 
and fourth feet. The borings made in late summer show no available water to a 
depth of 4 feet. The desert-sage has not been found on the moister lands where 
there was available moisture in all 4 feet in the late summer. Even as early as 
March there was rarely any available moisture in the third or fourth foot. Some¬ 
times only the first foot was wetted by winter rains (samples 4 and 5, Table X). 
