168 THE SALTON SEA. 



ground around the bases of the trunks, but no measure of the penetration could be made. 

 Some of these trees survived. The fruits are probably capable of enduring even a higher 

 proportion of salts, since a rank of plantlets was found at the upper margin of the shelf 

 laid bare at Travertine Terraces in 1908, also at the upper margin of the emersions of 1910, 

 191 1, and 1912. The low rate of recession during the winter, coupled with the violent wave- 

 action, is responsible for the small cut bank which separates the emersion of one year from 

 that of the next. It was just under this bank that the dense row of this tree was established, 

 which is indicative either of a dispersal of fruits before niid-winter and their germination 

 early in the year, or of early maturation of fruits in the spring and their inmiediate lodg- 

 ment in the angle at the foot of the upright bank. The flying fruits fill the air at the time 

 of their ripening and many might fall directly on the ground, or upon the water a few feet 

 or a few hundred yards away and be washed ashore. (Plates 24 a and 26 b.) 



Psathyrotes ramosissima appeared on the beach laid bare in 1907 on Obsidian Island. 

 It was seen first in February 1908 and was fruiting in May of the same year. Despite this 

 production of seeds, it did not reproduce itself and was not seen again here or elsewhere in 

 the emersed zones. The only assignable cause of its defection would be the toxicity of 

 the soil salts increasing with desiccation. 



Salix nigra like Populus survives the submergence of its roots in water slightly saline, 

 as was shown by the behavior of many trees on the Mecca beach. The seeds likewise 

 appear to germinate in the presence of some concentration of salts. The occupation of 

 the beaches by seedlings was confined to the western shore of the lake. Some were seen 

 at the foot of the long bajadas southeast of the Travertine Terraces and this plant formed 

 the most prominent feature of the dense rank of perennial plants which was formed at 

 the upper margins of the emersions of each year. It appears on the records for 1907 and 

 1908, but disappeared from both within a year. But one Salix was present on the 1909 

 emersion when it was examined in 1912. The invasion began to be heavier after this and 

 a crowded row of Salix as well as of Populus was found at the upper margin of the emer- 

 sion of 1910, in September of that year, which had persisted and by June 1912 had made a 

 rank of trees 10 to 15 feet in height which have continued to grow since that time. Another 

 heavy rank was formed at the upper margin of the emersion of 1912 and plantlets were seen 

 as early as June of that year. The species did not appear so early in 1912 and no plantlets 

 were found at the upper margin of the emersion in June 1912, but in mid-October young 

 trees 2 or 3 feet in height were present. (Plates 24 a and 25 b.) 



The dispersal of the seeds must be under much the same conditions as those of Populus. 

 The species was found only on the beaches of the western shores of the lake and no instance 

 was found of its transportation across the open lake to the emerging islands. Trees are 

 present at springs near Travertine Terraces and fruits may have lodged directly on the 

 moist strands or have fallen in the water and been washed ashore. Germination took place 

 in soil high in salt-content. 



Sphceralcea orcuttii was seen but once and then only in a single plant on the shore of 

 Obsidian Island in the path of the direct inflow current of the Alamo River, under the same 

 circumstances as Psathyrotes, but failed to reproduce itself. Both of these plants probably 

 floated to the place. 



Typha angustata was found in great abundance in the Delta and around many springs 

 in the Salton Sink. Its fruits must be carried widely by air-currents, yet its appearances 

 as a pioneer on the emersed strips were very few. It was first seen in the moist filled 

 channels of the old washes on Imperial Junction beach emersed in 1907, but these plants 

 succumbed to the increasing aridity within a year. Next it was a pioneer in the emersion 

 of 1908 on the Travertine Terraces, but these individuals perished with the desiccation 

 following recession. A single plant coming from a rhizome washed ashore was found on 

 the Imperial Junction beach in 1909 and much material of this plant was found at various 



