NATIVE WOODY PLANTS OF THE UNITED STATES 199 
Prosopis spp. Mesquites. 
Stomach records (in addition to specific records) : Scaled quail, antelope jack 
rabbit, gray-sided jack rabbit; Texas jack rabbit, Arizona cottontail, Holzner 
ecottontail. Observations (in addition to specific records) : Gambel quail, Mexi- 
can turkey, white-winged dove. 
Prosopis articulata, see Prosopis chilensis. 
Prosopis chilensis (Mol.) Stuntz. Mesquite. 
P. juliflora (Swartz) DC., P. velutina Woot., P. julifiora velutina (Woot.) 
Sarg., P. odorata Torr., P. articulata Wats., P. glandulosa Torr., P. juli- 
flora glandulosa (Torr.) Cockerell, Neltuma julifiora (Swartz) Raf., 
N. glandulosa (Torr.) Britt. and Rose, N. velutina (Woot.) Britt. and 
Rose. 
Range: 9, 11, 16, 17, 19, 20, 25, 29, 30. 
Site: Dry, well-drained, moist, sun. 
Fruit: Legume; available September—October, rarely July. 
A large, spiny shrub to a small or rarely large tree; adapted to a wide range 
of soil conditions; seedling with a taproot but mature plant with a generalized 
root system; roots penetrate as much as 60 feet below the surface and 30 feet 
is common; little damaged by insects or disease; much used locally for fuel; 
thicket forming; Shrubby in dry areas, larger and treelike in moist places; 
wood very hard and durable, often used for fence posts; underground stems 
enormous, locally an important source of fuel; commonly attacked by mistletoe; 
aggressive, apparently taking possession of grasslands, particularly when they 
are overgrazed; nearly impossible to kill by overgrazing; usually widespreading 
and lower when heavily grazed. 
Standley (539) points out that in Mexico so many intergrading forms occur 
that separation of P. chilensis into three or more species is impossible. He 
notes that Specimens from Peru and Argentina, if labeled from the United 
States, would be determined by a botanist as P. juliflora. (In an appendix he 
changes this name to P. chilensis). The variability of the species permits of 
many different forms, but from studies made by Standley of specimens from 
many localities, it would Seem most useful to consider all forms as one species. 
Stomach records: Five species of birds including scaled quail and Gambel 
quail; Mearn’s coyote, northern hooded skunk; composed 36 percent of food 
of antelope jack rabbit, and 56 percent of food of Arizona jack rabbit through- 
out the year in Arizona. 
Forage value for stock high; occasionally poisonous to stock if eaten to the 
exclusion of other forage; seeds pass out of the digestive tract of livestock 
unharmed, and in this condition are often eaten by birds, especially Gambel 
quail. An exceptionally good honey plant. Observations: Scaled quail; west- 
ern white-winged dove; captive porcupine (pods only) ; Texas antelope squirrel ; 
gray-tailed antelope squirrel; Harris ground squirrel; gray-spotted ground 
squirrel; Rio Grande ground squirrel; Mexican raccoon; coyote; Texas white- 
tailed deer; mule deer; rock squirrel. Far surpasses any other species in both 
frequency of occurrence and quantity taken in the food of Gambel quail; the 
buds and flowers are taken in spring, and in fall and winter seeds are eaten; 
these quail often use the rachides of the leaves in nest-building. 
A host for the mistletoe (Phoradendron californicum) which produces an 
abundant and almost continuous crop of berries. Phainopeplas, mockingbirds, 
sage thrashers, robins, and bluebirds depend almost wholly on these berries 
for food; they are also eaten by Gambel quail. The Abert towhee, Crissal 
thrasher, phainopepla, and Lucy warbler commonly breed in the mesquite 
association. 
Prosopis cinerascens Gray. Screwbean. 
Strombocarpa cinerascens Gray. 
Range: 11, 17. 
Site: Dry, sun. 
Fruit: Legume. 
A small, spiny shrub. 
Prosopis glandulosa, see Prosopis chilensis. 
Prosopis juliflora, see Prosopis chilensis. 
Prosopis odorata, see Prosopis chilensis. 
