igO MISC. PUBLICATION 303, U. S. DEPT. OF AGRICULTURE 
A large evergreen tree ; fire-neeclled ; adapted to many kinds of soil ; seedlings 
form large taproots; difficult to transplant; very intolerant of shade; sus- 
ceptible to blister rust; most seed is produced by trees in open stands at low 
altitudes; long-lived; wood soft, of value commercially; 5,400-5,600 seeds per 
pound, germination 36 percent. 
Stomach records: Two species of birds, including grouse. Observations: 
Porcupine, spruce squirrel, Fremont squirrel ; mucb eaten by birds and squirrels 
generally. 
Pinus glabra Walt. Spruce pine. 
Range : 29, 30. 
Site: well-drained, moist, sun, shade. 
Fruit: Cone. 
A large evergreen tree; two-needled; growth remarkably rapid; wood soft, 
of some value commercially ; 77,500 seeds per pound. 
Stomach records: Bobwhite, squirrel. 
Pinus heterophylla, see P. caridaea. 
Pinus jeffreyi Murr, Jeffrey pine. 
P. ponderosa jeffreyi Vasey. 
Range: 4. 
Site : Well-drained, sun. 
Fruit: Cone. 
A large evergreen tree; three-needled; appears to intergrade with P. po^i- 
derosa; tolerant of shade in early stages, later intolerant; produces seed pro- 
lifically; wood of great commercial value; 3,100-3,300 seeds per pound; seeds 
from large cones complete their germination 2 weeks before seeds from small 
cones. 
Stomach records: Four species of birds, including quail and Mount Pines 
grouse. Observations: Clark's nutcracker; Columbian gray squirrel, Sierra 
chickaree, Tahoe chipmunk, Allen's chipmunk ; commonly much eaten by birds 
and rodents ; of slight importance as brows© for mule deer. 
Pinus lambertiana Dougl. Sugar pine. 
Range: 1, 4, 10. 
Site: Well-drained, sun. 
Fruit : Cone ; ripe in August of the second season, seeds shed in October, 
cones falling the following year. 
A very large evergreen tree ; largest of all pines ; five-needled ; susceptible to 
blister rust; very intolerant of shade except in the seedling stage; wood soft, 
of high commercial value ; 2,300 seeds per pound, germination 65 percent. 
Observations: Porcupine, Columbian gray fox. Sierra chickaree, Allen's chip- 
munk, long-eared chipmunk, California gray squirrel ; of slight importance as 
browse for mule deer. 
Pinus lasiocarpa, see Abies lasiocarpa. 
Pinus leiophylla Schlecht. and Cham. Chihuahua pine. 
P. cl\iliual\uana Engelm., P. leiophylla chihuahuaua Shaw. 
Range: 11, 14. 
Site : Dry, well-drained, moist, sun. 
Fruit : Cone ; mature in September of the third season, often persistent 
closed 5 or more years. 
A large evergreen tree; commonly three-needled; intolerant of shade; wood 
of importance commercially but only a small supply is known. 
Observations: Much eaten by thick-billed parrots. 
Pinus mitis, see Pinus echinata. 
Pinus monophylla Torr. and Frem. Singleleaf piiion. 
P. cembroides monophylla Voss.. Caryopitys monophylla (Torr. and Frem.) 
Rydb. 
Range : 4, 5, 9, 10, 13, 14. 
Site: Dry, well-drained, sun. 
Fruit : Cone ; mature in August of the second season, seeds shed in 
September. 
A small to large, flat-topped evergreen tree ; commonly one-needled ; very local 
in occurrence ; endures extreme drought in its native habitat ; very slow grow- 
ing; intolerant of shade; wood much used for fuel locally: 1,200 seeds per 
pound. 
