1904] MAC DOUGAL—DELTA AND DESERT VEGETATION 45 
ary across a typical portion of the desert mesa was the route followed 
by Mexican prospectors rushing to the Californian gold fields in 
1849, and in the waterless stretch of 1 50%" between Quitovaquito 
and Tinajas Altas may be counted over four hundred small circles 
and crosses of loose stones by the side of the trail, grim evidences of 
failures to negotiate this formidable “Jornada del Muerto.” 
Attempts to penetrate the desert directly from the coast. have met 
with equally serious difficulties. The shore is fringed with mud flats 
many kilometers in width, and numerous sand bars bare at low 
water; the tides rise 4-10™ and produce currents that run 4-8'™ per 
hour, forming waves or bores that sweep up the river, at times endan- 
gering all craft not in protected anchorages. But few sheltered anchor- 
ages are to be found in the upper Gulf, and nearly all of these are far 
from a supply of fresh water. The few expeditions to this region in 
Which attention was paid to the flora are easily recounted. 
Colonel Andrew B. Gray traversed the desert from the inter- 
national boundary to Adair Bay in 1854, discovering the singular 
parasitic Ammobroma Sonorae Torr.,? which fastens to the roots of 
Franseria and Dalea at depths of 60-120°™ in the sand, and sends 
its fleshy stems to the surface, on which the flowers appear to rest. 
Dr. E. Palmer traveled southward from Yuma to Lerdo near the 
head of tidewater in 1889, and collected about two dozen species of 
plants,3 but no general account of the expedition is available. 
Descriptions of a number of the plants are to be found’in the 
accounts of the boundary survey,+ in which but little attention, 
however, appears to have been paid to the flora of the delta. 
Les: Brandegees made a long journey overland, in the same 
year in which he traversed Baja California, for a distance of several 
hundred miles northward to San Quintin in about the same lati- 
tude as the southernmost point reached by my own expedition. How- 
ever, he did not reach the country east of the main divide north of 
San Luis Bay, 300*™ south of the mouth of the river. 
> Torrey, J., Ammobroma, a new genus of plants. Ann. Lyc. Nat. Hist. N. Y. 
8: June 1864, 
3 Ross, J. N., Contrib. U. S. Nat. Herb. 1:27. 1890. 
+ Report on U. S. and Mex. Boundary Survey, Emory 2:21. 1859. 
SBR ANDEGEE, T. S., A collection of plants from Baja California, 1889. Proc. 
Calif. Acad. 2 fie eee 1889. 
