"1p Petioles ‘laterally flattened, especially near the base 
4 of the leaf; leaves green on both surfaces 
2, Leaves ovate to rotund, rounded to subcuneate at the ; g 
G& base, rarely over 5 cm. long; capswe valves 2 i. Be tremuloides 
2, Leaves deltoid-ovate, with a broad shallow sinus at 
(, the base, 6-10 cm. lony or more; capsule valves 35-4 2, P. Sargentii 
OQ Petiodles columnar or nearly so; leaves silvery or rusty 
4 beneath 
2 Leaves prevailingly rounded at the base; pods 
, pubescent, the pistillate catkins 6-12 cm. 
@ 6 “long; young bark usually silvery grey 3, BP. trichocarpa 
q) p Leaves prevailingly cordate at the base; pods 
, solabrous, the pistillate catkins 10-15 or 
ap as 25 cm. long; young bark usually rusty 
or yellowish tinged 4. Ee balsamifera 
1. #. tremmuloides Michx. var. (Tides.) Daniels. Aspen. A slender, 
eracef Ugyege 6-20 me tall, the bari: white at a distance ,folivecsous on closer 
serutiny, covered with a white powder, dark gray and furvoweu only at tne base 
in elder trees (40-45 cm. in ciameter); leaves commonly 3-5 cm. long 
juvenile meieim@eroccasio wcll; 10-le cm. long) Leaves, ovate to nearly orbicular, 
very blunt or abruptly acuminate, rounded to subcuneate at the base, auil 
CYre@n Sterpempaesmeimess, li-nter beneath, amugg@ crenatel, serrate, @apereeqtar 
younded-end-curuinertommmem , octioles slender, flattened laterally near the 
base of the leaf, pubescent, 1/2 to 2/3 the len yth_of the blade; catkins 5-6 cn, - bey 
Vv 
lastrovs) sore the pistillate increasing to 10 cn. fatanasuraay ; bracts o-5 lobed, 
a 
sTrous soitlyJhairy; stamens commoniy 68-10; ovary glabrous, narrowly conical; style 
short and thick; stigmas 2, fringed; capsules lanceolate in outline, 6 mn. long, 
e-valved. f 
- tual yt ech 
burns up tc 50 years old or in open ,patcnes in mture forest, 
but disappearing rapialy with the srowth of the forest. 
Commonly found in smali gaa reaching its ereatest Gevelopment below 5000 feet 
in the broader valleys in springy places or lake embayments, where it may rarely 
reach a height of 100 feet and DeBeHe of «2 inches. ‘The leaves dance and 
slisten in a licht wind, marking the tree at a distance and making a Character- 
ww istic rustling sounde ‘hrouchout our region but infrequent abLove 4000 feet. 
