SALICACEAE, 9 
Poprutus. Poplar. 
(Family Salicaceae). 
Trees: deciduous. Bark at first 
usually smooth and green or whit- 
ish or orange, gray and often 
deeply fissured in age. Wood rath- 
er soft, white becoming brownish, 
minutely diffused-porous with 
fine medullary rays, satiny when 
split. Twigs moderate, terete or 
5-angled: pith rather small, 5-an- 
gled, subcontinuous, brown. Buds 
moderately small, ovoid or 
elongated, appressed or sometimes 
outcurved, sessile, solitary, with 
several exposed scales of which 
the lowermost is immediately over 
the leaf-scar. lLeaf-scars_ alter- 
nate, somewhat raised, broadly 
' erescent - shaped to. triangular. 
somewhat 3-lobed, large: bundle- 
traces 3, often compound: stipule- 
scars narrow. 
The poplars possess many winter differences besides those 
used in the present key. The bark is differently roughened: 
in the native cottonwood gray and grooved between flat-topped 
ridges, while in the commonly planted ‘Carolina cottonwood” 
(xP. Eugenei), as in the Lombardy poplar which is one of 
the parents of this, it is dark with pale fissures between rather 
sharp ridges. On young trunks, and the branches of older 
trees, the smooth bark is colored in a characteristic fashion: 
olive in the Lombardy poplar, orange in many “Carolina” 
poplars, greenish-white in the large-toothed aspen, and some- 
times almost chalky white in the silver poplar and our native 
aspen. 
