492 
SALICACEAE. 
5. Populus heterophylla L. Swamp or Downy Poplar. (Fig. 1168.) 
Populus heterophylla I,. Sp. Pl. 1034. 1753. 
An irregularly branching tree, sometimes So° 
high and with a trunk 3° in diameter, the bark 
rough. Young foliage densely tomentose. Leaves 
long-petioled, broadly ovate, obtuse or subacute at 
the apex, rounded, truncate or subcordate at the 
base, crenulate-denticulate, 5’-6’ long, or those of 
young plants much larger, glabrous or somewhat 
floccose beneath when mature; petioles terete; 
bracts glabrous or nearly so; staminate aments 
stout, 3/-4’ long, 9’/-12’’ in diameter, drooping; 
stamens numerous; pistillate aments raceme-like, 
peduncled, erect or spreading, loosely flowered; 
capsules ovoid, acute, 2-valved, 4/’-6’ long, shorter 
than or equalling their pedicels. 
In swamps, southern Connecticut and New York to 
Georgia, west to Louisiana, north in the Mississippi Val- 
ley to Indiana and Arkansas. Wood soft, weak, com- 
pact, brown, weight per cubic foot 26 lbs. April-May. 
6. Populus grandidentata Michx. Large-toothed Aspen. (Fig. 1169.) 
— \ 
Populus grandidentala Michx. F1. Bor. Am. 2: 243. 1803. 
A forest tree with smooth, greenish-gray bark, 
maximum height about 75°, and trunk diameter 
2%°. Leaves ovate-orbicular, those of very young 
plants densely white-tomentose beneath, some- 
times 1° long, with irregularly denticulate margins, 
those of older trees tomentose when young, gla- 
brous when mature, short-acuminate, coarsely un- 
dulate-dentate, obtuse or truncate at the base 214/- 
4/ long; petioles slender, flattened laterally; bracts 
silky, irregularly 4-7-cleft; staminate aments 2/— 
4’ long, about 5’’ in diameter, drooping; pistillate 
aments somewhat pubescent, dense, 3/-5’ long in 
fruit, also drooping; stigma-lobes narrow; capsule 
conic, acute, 2-valved, about 3’’ long, rather less 
than 1/’ in diameter, papillose. 
In rich woods, Nova Scotia to Ontario and Minne- 
sota, south to New Jersey and in the Alleghanies to 
North Carolinaand Tennessee. Wood soft, weak, light 
brown, compact; weight per cubic foot 29lbs. April. 
can Aspen. 
7. Populus tremuloides Michx. Ameri- 
(Fig. 1170.) 
Populus tremuloides Michx. Fl. Bor. Am, 2: 243. 1803. 
P. Atheniensis Ludwig, Neue Wilde Baumz. 35. 1753-(?) 
A slender tree, with smooth, light green bark, 
reaching a maximum height of about 100° and a 
trunk diameter of 3°, the young foliage glabrous, 
excepting the ciliate margins of the leaves, Pet- 
ioles very slender, flattened laterally, causing the 
leaves to quiver in the slightest breeze; leaves 
broadly ovate or orbicular, short-acuminate at the 
apex, finely crenulate all around, truncate, rounded 
or subcordate at base, 1/-2'4’ broad, or those of 
very young plants much larger; bracts silky, deeply 
3-5-cleft into linear lobes; aments drooping, the 
staminate 1%4/-214’ long, 3/’-4’’ in diameter, the 
pistillate longer, dense; stigma-lobes linear; cap- 
sule like that of the preceding species, but some- 
what smaller. 
In dry or moist soil, Newfoundland to Hudson Bay and Alaska, south to New Jersey, Pennsylvania, 
Kentucky, in the Rocky Mountains to Mexico and to Lower California. Ascends to 3000 ft. in the 
Adirondacks. 
Wood soft, weak, light brown; weight per cubic foot, 25 lbs. March—May. 
