200 MISC. PUBLICATION 303, U. S. DEFT. 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 bob white, road runner, Gambel quail. Much 

 browsed by livestock, and pods used for fodder. 



Prosopis velutina, see Prosopis vhilemis. 



Prtmus 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 of 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 July-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, (pi. 25, B). Wild plum. 



Range : 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30. 

 Site: Dry, well-drained, moist, sun, shade. 

 Fruit : Drupe, available July-October. 



