IMPORTANT WESTERN BROWSE PLANTS 93 
Texas to Arizona and southward, has no known economic value but 
appears to have active chemical properties. 
MILKWORT FAMILY (POLYGALACEAE) 
This family is represented in the West by about 35 species, of 
which all but one, the southwestern annual, Monnina wrightii, be- 
long to the genus Polygala. Of the western species of Polygala, 
about half are annual or perennial herbs, a very few (e. g., thorn 
polygala, P. acanthoclada, an ashen-hued, desert species ranging 
from western Colorado to southern California and Arizona) are 
definitely shrubby and about 1 to 4 feet high, while the residue 
represent varying degrees of undershrubbiness. Polygalas are typi- 
cal of warm regions, the genus being best represented in the South- 
west. The herbage of these plants, with their acrid milky juice, has 
a disagreeable flavor and is distasteful to grazing animals. Most, if 
not all, polygalas evidently have active chemical properties and at 
least one species, seneca-snakeroot (P. senega) is used in medicine. 
A number of the species are very showy when in full bloom, e. g., 
spiny polygala (P. subspinosa), a dwari spiny-tipped bush of the 
Great Basin and Southwest. 
SPURGE FAMILY (EUPHORBIACEAE) 
This very large, natural plant family produces the greater part 
of the rubber of commerce. It is represented in the West by at 
least 24 genera and 170 species. The spurge family is typical of 
hot, dry climates and, as would be expected, is best developed in 
the region from western Texas to southern California, the number 
both of genera and species increasing rapidly as the Mexican border 
is approached. Probably the majority of western spurges are her- 
baceous, but a considerable proportion are shrubs or undershrubs, 
notably Bernardia myricaefolia, which grows from western Texas 
to southeastern California and south into Mexico mainly in deserts. 
Others include certain species of the genera Acalypha, Adelia 
(=Ricinella), Andrachne, Croton, Ditaxis, Jatropha (=Mozzina), 
Manihot, Securingea, Tetracoccus, Tithymalus, and Trichosterigma. 
Florida has three tree genera of this family, including the notorious 
“deadly ” manchineel (Hippomane mancinella), but no western 
spurges are known to be arborescent. ; 
The acrid, milky, more or less poisonous juices prevalent in this 
family preclude the possibility of any of the species being eaten 
by livestock unless severe drought or near-starvation conditions ob- 
tain. If the plants are cropped to any material degree (especially if 
in fruit), symptoms of poisoning may be anticipated. Under west- 
ern range conditions, however, livestock losses from spurges appear 
to be very rare indeed, and there is no doubt but that at least goats 
and cattle often nibble species of Tithymalus, and perhaps other 
spurges as well, without any apparent injury. However, the 
herbaceous beetle spurge (Tithymalus crenulatus, syn. Euphorbia 
crenulata) and Palmer spurge (7. palmeri, syn. #’. palmert) are 
suspected by cattlemen on the Stanislaus National Forest, Calif. 
T. palmeri is reported as abundant on an area of that forest where 
losses took place in 1915. Crotonbush (Croton fruticulosus), a low 
