Jan., 1905.] Key — Poplars in Winter Condition. 
271 
KEY TO OHIO POPLARS IN THE WINTER CONDITION. 
JOHX H. SCHAFFNER. 
Popidus L. Trees with light soft wood; the larger branches 
usually with greenish -white, greenish, or brownish-gray bark. 
Twigs with a terminal bud; buds more or less resinous but not 
spicy-aromatic to the taste or smell; outer bud scales several, 
glabrous, pubescent, or tomentose; leaf scars alternate, not 2- 
ranked, more or less heart-shaped ; bundle scars 3 ; stipular scars 
evident; self-pruning scars present and often very prominent; 
bark bitter; pith .5-angled, solid. 
1. Twigs white or gray tomentose; buds ovoid-conical, short pointed. 2.. 
1. Twigs glabrous or pubescent, not tomentose. 4. 
2. Buds glabrous, or slightly pubescent or tomentose, resinous, large; 
twigs robust, usually angular; leaf scars large. 
P. heteropliyUa L. Swamp Poplar 
2. Buds tomentose or very pubescent, only slightly resinous, reddish- 
brown; twigs usually terete and slender; bark of larger branches 
greenish-gray or greenish-white. 3. 
3. Buds verj’’ tomentose, small; twigs usually with abundant self-pruning 
scars which heal very perfect!}’, showing a dark ring around a cen- 
tral depression; bark often with black, diamond-shaped scars; 
crown large, spreading, round-topped. P. alba L. White Poplar. 
3. Buds pubescent, not tomentose, rather large; bark of larger branches 
greenish-gray; trunk erect with an open, unsymmetrical straggling 
crown; branches distant, small and crooked. 
P. grandidentata ilx. Large-toothed Aspen. 
4. Terminal and lateral buds rounded or only slightly angular, rather 
short pointed, brown and polished or reddish-brown and pubescent ; 
twigs usually slender and terete. 5. 
4. Terminal bud angular, large, rather long pointed; lateral buds long 
pointed or acuminate, sometimes angular. 6. 
5. Buds glabrous or nearly so, brown and polished; bark of larger 
branches smooth, light green. 
P. tremuloides ^Ix. American Aspen 
5. Buds pubescent and reddish-brown; bark of larger branches smooth, 
greenish-gray. P. grandidentata Mx. 
6. Tree spire-like, the branches nearly vertical; lateral buds acuminate, 
curved, usually spreading. 
P. dilatata Ait. Lombardy Poplar. 
6. Tree dome-shaped, the branches spreading. 7. 
7. Buds gummy resinous, reddish-brown and large; twigs often more or 
less pubescent, usually reddish, mostly terete. 
P balsamifera L. (Inc. var. candicans). Balsam Poplar 
7. Buds resinous but dry, greenish or yellowish-gray; lateral buds 
acuminate, and ttsually curved and spreading; twigs glabrous, usu- 
ally brownish-gray, often angled. P. deltoides iMarsh. Cottonwood. 
