154 MISC. PUBLICATION 101, U. S. DEPT. OF AGRICULTURE ' 
as the common F, acanthicarpa and F. tenuifolia have a low pala- — 
tability for cattle and sheep and the former is medicinal among the _ 
Zuni Indians (129). 
Triangle bur-sage (/. deltoidea, syn. Gaertneria deltoidea), some- 
times called snakeweed, is a low shrub or undershrub 10 to 24 inches 
high. Although common in dry foothills and mesas of low eleva- — 
tion in central and southern Arizona, it is worthless as a forage plant. 
White bur-sage (/. dumosa, syns. F. albicaulis, Gaertneria 
dumosa), locally known as burroweed and sand bur, is a low, 
whitened, brittle-branched, somewhat spiny-twigged bush, ranging 
from southern California to southwestern Utah and south into Mex- 
ico. It is one of the commonest and most abundant desert shrubs of 
the Southwest, is a frequent associate of creosote bush, and has the 
characteristic desert habit of leafing and greening out after rains and — 
drying up in the interim. Oddly enough this shrub has quite a local 
reputation on desert sheep and cattle range, the burlike fruits espe- 
cially being considered very nutritious and fattening (724), and 
Coville (26) reports that.in the Death Valley region and vicinity 
the herbage of this species is preferred by horses to that of all other 
desert shrubs. Palmer (738) ascertained this to be one of the two 
chief host plants of the curious, parasitic, lennoaceous plant sand- 
root (Ammobroma sonorae), known also as sandfood and camote, 
whose succulent stems with a fiavor reminiscent of sweetpotatoes, are 
a valuable source of food supply to the Cocopa Indians and to desert — 
travelers. 
OTHER GENERA 
Burrobrush (Hymenoclea monogyra) (pl. 12, A), a diffuse, 
branched shrub, also known as arrowwood and romerillo, is of 
chief importance because of its abundance. It is 2 to 614 feet high, 
with slender stems and usually fine-dissected leaves, and is found 
mostly in sandy or gravelly soils along or near streams and in ar- 
royos, canyons, washes, and bottom lands, and to a much lesser extent 
on mesas and foothills, chiefly in the mesquite-covillea belt, usually 
at not over 4,500 feet elevation and probably never over 5,500 feet. 
It often forms dense thickets in deep sand along streambeds where 
it is valuable in erosion control. Its geographical range is from 
western Texas to southern California, almost throughout Lower 
California, and in adjacent Sonora, Sinaloa, and Chihuahua. 
The common name “burrobrush” alludes to the usual observa- 
tion that nothing but burros will eat it. While sometimes exten- 
sively cropped on overgrazed range, the foliage of burrobrush is | 
somewhat acrid and usually seems to be unpalatable, and in many 
places the bush is considered worthless except, to some extent, when 
growth starts. Bailey (5) compares the white juicy buds and sprouts 
of this species to fresh, crisp heads of lettuce and states that they J 
are an important source of water and food for desert rodents, espe- 
cially the kangaroo rat (Dipodomys merriamz); he estimates the — 
water content of these parts at 90 per cent. 
The species may have potential use in artificial planting to control — 
erosion, especially in sandy washes and the like; it seems to be well _ 
intima Me eis 
