326 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM, 
Eriogonum polifolium Benth. 
Noted in abundance at elevations ranging from about 780 meters in Trinidad Valley 
up to about 2,100 meters on open, brush-covered, southerly slopes along the west 
side of the San Pedro Mértir Mountains. It grows as a shrub 60 to 90 cm. in height. 
Specimens in flower were taken at Arroyo de Ledén, near Trinidad Valley, July 4. 
Eriogonum trichopodum Torr. 
In the sandy and gravelly desert region near Agua Dulce, 30 miles southeast of 
San Fernando, this Eriogonum was one of the characteristic species. It grows to a 
height of 60 to 90 cm., but the slender, hairlike branchlets render it almost invisible 
at. a short distance. It was associated here with E. fasciculatum and, like that spe- 
cies, was not observed farther south. A flowering specimen was taken at Agua Dulce, 
September 9. 
CHENOPODIACEAE. Goosefoot Family. 
Atriplex canescens (Pursh) Nutt. CHAMISO. 
Various species of Atriplex are commonly called “chamiso” in Lower California. 
In the San Pedro Martir Mountain region A. canescens ranges widely in both the 
Upper and Lower Sonoran zones, and extends southward to an undetermined limit. 
It is the principal shrub at about 810 meters over Lower Sonoran parts of the bottom 
of Trinidad Valley, whence it reaches eastward through San Matias Pass and in less 
abundance upward over open Upper Sonoran mountain slopes to at least 1,500 meters 
altitude. One or more forms of the A. canescens type are among the most abundant 
desert shrubs, ranging at low elevations nearly throughout the Peninsula. Thickets 
in which Atriplex, Covillea, Simmondsia, and Prosopis bushes are dominant afford 
cover and food for small desert mammals. The seeds of all these bushes are eaten 
by mammals, as shown by the fragments of seed capsules left about the entrances to 
burrows or under rocks where they have been carried and left by the animals. Specti- 
mens of A. canescens were collected in Trinidad Valley and San Matias Pass. 
Atriplex linearis 8, Wats. CHAMISO, 
A specimen referred to this species by Mrs. K. Brandegee was taken at Tinaja de 
San Esteban, 25 miles north of San Ignacio, where it grew as a shrub 1.2 to 2.5 meters 
in height. The species, much resembling A. canescens, was originally described 
from Guaymas. Mr. Brandegee records it from San Jorge and La Paz. 
Atriplex barclayana (Benth.) Dietr. CHAMISO, 
Along the route from Calmallf to San Ignacio this species was seen in abundance. 
It forms thickets in soft soil along arroyos, avoiding stony hillsides. It grows as a 
shrub 90 to 120 cm. high, with somewhat drooping habit. A specimen was col- 
lected at Tinaja de San Esteban, 25 miles north of San Ignacio. Brandegee records 
it from Magdalena Island. 
AMARANTHACEAE. Amaranth Family. 
Celosia floribunda A. Gray. 
This species was abundant in the valley at Comandt, growing as a shrub 1.2 to 1.8 
meters high. A flowering specimen was collected November 6. Brandegee like- 
wise records this species from Comand4, as also from San José del Cabo and Todos 
Santos in the Cape District, and says it seems to reach its greatest development along 
the streams north of Todos Santos, sometimes forming small trees. 
