NATIVE WOODY PLANTS OF THE UNITED STATES 197 
lived; easily damaged by fire when young, less so with age; much attacked 
by fungi; easily storm damaged; fairly wind-firm; 1,860,000 seeds per pound, 
germination 60-90 percent, vitality transient; stump sprouts and root sprouts 
produced; has been successfully used in checking erosion and in fixation of sand 
dunes; wood used commercially; grows on coal-stripped lands in Illinois. 
Stomach records: Black-tailed deer. Observations: Evening, and rose-breasted 
grosbeak ; cottontail rabbit. Much browsed by cattle. 
Populus fremontii Wats. Fremont cottonwood. 
P. macdougalii Rose. 
Range: 1, 3, 4, 5, 9, 10, 11, 13, 14. 
Site: Well-drained, moist, sun. 
Fruit: Capsule. 
A large tree; commonly occurs in sandy soil; grows well in saline soils; 
rapid growing, short-lived; wood used locally; much attacked by mistletoe. 
Several varieties are described, all occurring within the range of the species. 
Observations: California mule deer. 
Populus grandidentata Michx. Largetooth aspen. 
Range: 21, 22, 23, 25, 26, 27%, 28. 
Site: Dry, well-drained, moist, sun. 
Fruit: Capsule, available in May. 
A small to large tree; grows in sand, humus or loam; root system shallow ; 
very rapid growing, short-lived; often Severely injured by fungi, fire, wind, and 
insects; wood used commercially ; a pioneer in burned and cut-over land; germi- 
nation percentage of seeds high, vitality transient. 
Observations: Cottontail rabbit, white-tailed deer. 
Populus heterophylla L. Swamp cottonwood. 
Range: 25, 27, 28, 29, 30. 
Site: Moist, sun. 
Fruit: Capsule, available in May. 
A large tree; root system very shallow; rapid growing, short-lived; subject 
to heart rot at maturity; wood of importance commercially. 
Populus macdougalii, see Populus fremontii. 
Populus mexicana, see Populus arizonica. 
Populus occidentalis, see Populus sargentii. 
Populus palmeri Sarg. Palmer cottonwood. 
Range: 16, 20. 
Site: Well-drained, moist, sun. 
Fruit: Capsule. 
A large tree. 
Papulus sargentii Dode. Sargent cottonwood. 
P. deltoides occidentalis Rydb., P. occidentalis (Rydb.) Britt., P. angulata 
Port. and Coult. 
Range: 12, 13, 14, 15, 16, 18, 19, 21. 
Site: Well-drained, moist, sun. 
Fruit: Capsule. : 
A large tree; rapid growing, short-lived; wood used to some extent locally. 
Populus tacamahaca, see Populus balsamifera. 
Populus texana Sarg. Texas cottonwood. 
Range: 16. 
Site: Well-drained, moist, sun. 
Fruit: Capsule. 
A large, short-lived, rapid-growing tree. 
Populus tremuloides Michx. (pl. 24, A, B,). Quaking aspen. 
P. aurea Tidest., P. vancouveriana Trel., P. cercidiphylla Britt. 
IRIS 6 2 Ay as (UG fe Gh allo as IBY a ley aU Ol) a OR Oh Gas Oye rd, 
Site: Dry, well-drained, sun. 
Fruit: Capsule, available May-June. 
A small to large tree; occurs in many soils; apparently not satisfactory in 
pure plantations owing to insects and disease; root system shallow; will grow in 
many soils but apparently does best in sandy loam; very rapid growing, short- 
lived; easily and seriously damaged by fire, wind, fungi, and insects; wood 
