200 MISC. PUBLICATION 3038, U. S. DEPT. OF AGRICULTURE 
Prosopis pubescens Benth. Screwpod mesquite. 
Range: 9, 10, 11, 17. 
Site: Dry, well-drained, moist, sun. 
Fruit: Legume, available July—October. 
A large shrub to small or large tree; spiny; occurs in sandy loam, gravel, 
and other soils; has a tendency to grow in thickets; wood very durable in con- 
tact with the soil, of importance locally. 
Stomach records: Masked bobwhite, road runner, Gambel quail. Much 
browsed by livestock, and pods used for fodder. 
Prosopis velutina, see Prosopis chilensis. 
Prunus spp. Cherries, plums. 
Trees or shrubs commonly divided into two classes, the cherries and the 
plums; most species are in general rather easily damaged by fire; constant 
cropping of the twigs leads to much suckering in the plums, which in turn saps 
the vitality of the root system. 
Considerable discussion, in print and out, has resulted in causing the genus 
to be regarded with suspicion, as far as the poisonous qualities of some species 
are concerned. The statement that leaves in a wilting condition are poisonous 
is common. This may be a fallacy in view of work done at the New Hamp- 
shire Agricultural Experiment Station (Dayton, 158). However, parts of 
the plants contain varying quantities of amygdalin, a glucoside which, with the 
proper enzyme, yields hydrocyanic acid. The glucoside is present in leaves, 
bark, and especially in the seed, but never in the fruit pulp. In the eastern 
chokecherries the young vigorous leaves and tenderest shoots develop most of 
the cyanogenetic materials, and therefore in that region cattle should not be 
permitted to graze too early in the season in pastures where cherry is growing 
and should never be permitted to gorge themselves upon it. Hungry sheep 
should never be driven along trails lined with cherries. The pits, which are 
most poisonous, are never eaten by livestock. Birds, rodents, and other mam- 
mals are fond of the fruits and are considered to be largely responsible for 
the dissemination of the species. 
Stomach records (in addition to specific records) : Sixty-nine species of birds, 
including ruffed grouse, bobwhite, dusky grouse, sharp-tailed grouse, and ring- 
necked pheasant; composed 8.8 percent of winter food of ruffed grouse in 
New York, and 9.8 percent of winter food of ruffed grouse for the northeastern 
United States; red squirrel, gray eastern chipmunk, red fox, white-tailed deer; 
found in 71 skunk stomachs in New York; composed 6 percent of fruit food of 
eastern skunk in Michigan. Observations (in addition to specific records) : 
Thirty-two species of birds, including band-tailed pigeon, Gambel quail, dusky, 
gray ruffed, and ruffed grouse, emergency food cf northern sharp-tailed grouse; 
ranks nineteenth on the list of quail food plants of the Southeast; ring-necked 
pheasant; coyote, Say chipmunk, opossum, Douglas ground squirrel, raccoon, 
pica, and red fox, porcupine, Olympic wapiti, Wasatch chipmunk, Siskiyou 
chipmunk, rock squirrel; New Mexico black bear, Say’s ground squirrel. 
Browse value on sheep and cattle range is considerable, although most species 
do not resist overgrazing well. 
Prunus alabamensis Mohr. Alabama cherry. 
Padus alabamensis Small. 
Range: 27. 
Site: Well-drained, sun. 
Fruit: Drupe, available September—October. 
A large shrub to small or large tree; flowers in May. 
Prunus alleghaniensis Porter. Allegheny plum. 
Range: 27. 
Site: Dry, well-drained, moist, sun. 
Fruit: Drupe, available Juiy—August. 
A small to large shrub or small tree; flowers in April, commonly straggling ; 
thicket forming; flowers and fruit borne profusely; sprouts readily from in- 
jured or exposed roots. 
Prunus americana Marsh. (pl. 25, B). Wild plum. 
Range: 12, 13, 14, 15, 16, 17%, 18, 19; 20,) 21,22, 23) 245 25,927,428; 295480: 
Site: Dry, well-drained, moist, sun, shade. 
Fruit; Drupe, available July—October. 
