THE COLORADO DESERT 21 



of the vegetation, salt grass {Distlchlis spicata)^ Allenrolfea occi- 

 dentalism reed (^Phragmites pkragmites), and a rush {^Juncus coop- 

 eri) . This last plant grows in enormous tufts, and is of pi-onounced 

 effectiveness as a soil builder. In some of the moister springs, with soft 

 deep black mud, a three-angled spike xu?>h. {Scirptis olneyi) was found, 

 and in others the arrows w^eed of the desert marshes ( Tessaria bore- 

 alis) (Plates XXIII and XXIV). 



The visitor to Salton should bring his own supplies and camp outfit 

 as no accomodations or supplies are available. 



One of the most convenient points from which to visit the native 

 palm groves of the Colorado desert is the town of Indio. The San 

 Bernardino mountains, high and timbered in their main western por- 

 tion, send out eastward for many miles into the desert a low timberless 

 spur. Its parched rocky slopes seem, at the distance of a few miles, 

 to be devoid of any vegetation whatever, but upon closer inspection 

 are found to be sparsely dotted with bushes, like the plains portion of the 

 desert. The canyons of this spur open out upon the valley in broad 

 deltas of gravel brought down by occasional torrents. Just within the 

 mouths of some of the canyons occur groves of a native fan leaved palm 

 (^Neowashingtonia Jilifera) . The groves visited by us were not those 

 nearest the town, about five miles, but those to which we were guided 

 under the name Thousand Palms canyon, about nine miles from Indio. 



The ordinary diameter of the trunk is about two feet and the trees 

 at full maturity are about fifty feet high. Most of the old trunks are 

 blackened, apparently by fire. The younger trees retain their dead 

 leaves for several years, folded downward over the trunk and forming 

 a cylindrical mass about eight feet through and sometimes eighteen 

 feet in height. As the trees grow taller the lower of these dead leaves 

 fall to the ground, leaving a naked trunk with a head of green leaves at 

 the summit and a collar of dead leaves just underneath (Plate XXV). 



All the trees seem to stand on the same general level, not far above 

 the base of the range. A close inspection showed that they grew in a 

 moist clay soil, incrusted with alkali. Apparently such rain as falls 

 upon the mountains and sinks into the earth is caught upon this clay 

 table and runs over it to the exposed margin, where for several miles 

 it forms a line of miniature oases containing the palms and various 

 plants characteristic of alkaline springs (Plate XXVI). These include 

 mesquite bushes {Prosopis)^ salt grass {Distic/ilis spicata)^ a rush 

 {Juncus)^ a sedge ( Cyperus^^ and an orchid (^Epipactis gigantea) . 

 Within the canyon and upon the delta were found a few desert shrubs 

 not met with earlier, the leguminous Parosela spinosa and another 



