September 26, 1908 61 
reported from the Mojave river, but recent collections suggest 
that it may have been collected somewhat further east. 
Larrea had been the constant characteristic plant of the 
plains, and on the last day (24th) the “‘screw-bean”’ (Prosopis pu- 
bescens) was seen for the first time, ‘“‘and here among many new 
plants, a new and very remarkable species of Eriogonum (£. zz- 
Hatum) made its first appearance.” 
The trail now left the river, and turned northward to a 
spring still known as Agua de Tomaso. It was a region of des- 
olation, “but throughout this nakedness of sand and gravel were 
many beautiful plants, and flowering shrubs, which occurred in 
many new species, and with greater variety than we had been 
accustomed to see in the most luxuriant prairie countries. Even 
where no grass would take root, the naked sand would bloom 
with some rich and rare flower, which found its appropriate 
home in this arid and barren spot.” Here he notes, “scattered 
over the plain, and tolerably abundant, a handsome leguminous 
shrub, three or four feet high, with fine bright-purple flowers.” 
He takes it to be ‘‘a new Psoralea,” but it was, of course, a Da- 
lea, and probably D. Fremontzz, a species collected in about the 
saine region by the Death Valley expedition. 
Continuing across this desolate country, on the 28th a large 
creek was reached, “of salt and bitter water, running in a west- 
erly direction. It is called by the Spaniards Amargosa, the bit- 
ter water of the desert.’ He came to the stream at its bend, and 
following up its ravine, “passed on the way a fork from the 
right, near which occurred a bed of plants, consisting of a re- 
markable new genus of Cruciferae.” This was described by 
Torrey in the appendix to Fremont’s Report as Oxystylzs lutea, 
and assigned to the Capparidaceae. It is an exceedingly local- 
ized plant, and was not again collected until 1891, when it was 
rediscovered by Mr. Coville, at about the type station. 
It is not our purpose to follow the party beyond the bound- 
ary of California. A long and devious journey, encompassed 
with danger, awaited them before they reached the Missouri 
