102 THE SALTON SEA. 



Its fruit is a pod tightly coiled in a cylinder 1 or 2 inches long, borne in close spikes of 

 from 2 to 12 pods. Both species have abundant bipinnate leaves with numerous leaflets, 

 which remain verdant throughout the summer, even in the more arid situations. 



Chilopsis linearis should not be included among the trees of the dry soils of the Sink, for 

 although of this class it is represented only by a few migrants which have been brought down 

 a wash from the neighboring canons, where it properly belongs and where it is abundant. 

 Those of this class which are authentic members of the Sink flora are Olneya tesota, Cercidium 

 torreyanum, and Parosela spinosa. All are here small trees, although elsewhere Cercidium 

 attains large dimensions. They grow in the detrital soils at the northern extremity of the 

 Sink, usually along or near washes, where there is likely to be attainable moisture within 

 reach of their roots. As their functional activity is largely suspended during the heated 

 months of summer their demand for water must be limited. None was seen in the compact 

 soils at the lower extremity of the Sink, or in the looser soil of the mounds. 



Olneya is a small tree, rarely over 15 feet in height. Two specimens near Mecca had 

 trunks respectively 35 and 49 inches to the branches and 62 and 42 inches in circumfer- 

 ence. The leaves are pinnate with but few and small leaflets, which had nearly all fallen 

 by the last of June, when the fruit was ripe. The pods are brown and closely pubescent, 

 and one- to three-seeded. I have not seen the flowers. Only the ultimate grayish twigs 

 appear chlorophyllous. 



The palo verde {Cercidium torreyanum) may attain in the Sink a height of 20 feet. 

 A specimen at Figtree John had a trunk 39 inches in the clear and 43 inches in circumfer- 

 ence. Usually there are two to five nearly equal stems from the same root. The leaves 

 are bipinnate and the few small leaflets are early deciduous, so that for the greater part 

 of the year the tree is leafless, but the photosynthetic function is carried on by the bright 

 green bark of the limbs and twigs. The large yellow flowers are produced in March and 

 April, when the leaves have already fallen, and in such profusion that the whole crown is 

 a mass of golden blossoms. The pods are numerous, 2 to 4 inches long, and constricted 

 between the seeds. They were quite ripe late in June and still pendant from the branches, 

 while in October they Uttered the ground beneath the trees. 



No specimen of Parosela spinosa with a single trunk was seen in the Sink, but always 

 there were two or more nearly equal stems springing from the same root, so that it appears 

 more a large shrub than a true tree. Twenty feet would be an extreme height, seldom 

 attained. One near Agua Dulce was divided at the surface of the ground into two branches, 

 respectively 44 and 30 inches in circumference. The wood is weak, so that old trees 

 are often spUt and splintered below by the bending of the stems beneath their heavy load 

 of branches and twigs. The leaves are very few in number and promptly deciduous, and 

 they have but two or three minute leaflets. The numerous branches divide and subdivide 

 into an intricate tangle of branchlets and twigs, almost gray in color. Some twigs are 

 slender spines on which the violet-blue flowers are produced in great profusion in June, 

 when the tree presents a very handsome appearance. The fruit probably ripens very 

 promptly, as do the fruits of the shrubby species of the genus, which grow in the desert. 



Of the eight trees of the Sink, excluding Chilopsis, five are leguminous, all of the 

 dry-land species being of this family. All five, notably the mesquite, are infested, often 

 heavily, with Phoradendron californicum, a leafless, slender-stemmed mistletoe, producing 

 abundant small red fruit. This commensal is an evident drain on the vitality of its hosts 

 and sometimes causes their death. 



