106 FLOWERS OF THE WOODS AND COPSES 
One seldom finds any Poplars in a really native state in any situation 
except in woods, for owing to their quick growth they are much 
planted in hedgerows and plantations. But the Aspen, which grows 
in damp, moist woods or by water, may well be native in such stations, 
and it is seldom found in any other habitat, as are the others which are 
also found in woods. 
The Aspen is an erect, rather distantly branched tree, with a rather 
short stem and slender branches. The bark is grey. The suckers are 
downy, as also are the buds, which are not clammy. The leaves are 
sub-entire, nearly round, broadly toothed, smooth both sides. The 
leaf-stalks are flattened. Those at the top are on long stalks, and are 
rounded with wavy margin. The radical shoots have short stalks and 
nearly triangular leaves. 
The blade of the leaf is inserted on the vertically flattened leaf- 
stalk, hence their tremulous character. Rain falls and runs down the 
petioles or stalks, where 2 cups catch and hold it, the cells being thin- 
walled secrete a resin, swelling when moistened, and the cells absorb 
the moisture, being protected in dry weather by the resinous deposit. 
The catkins are cylindrical, with hairy male catkin scales with 
narrow lobes. The 2 stigmas are divided into two nearly halfway, 
seared. 
The tree is 40-80 ft. high. It is in flower in March till April. 
The plant is a deciduous tree, propagated by seeds. 
Unlike the Willow, with the floral mechanism of which it agrees in 
most respects, the Aspen is pollinated by the wind, and has no honey. 
The stamens are more numerous than in Sa/zv, 4—30, the anther-stalks 
free, the stigmas are slender and 2~4-fid. 
The seeds are clothed in cottony appendages to aid in their dis- 
persal by the wind. 
The Aspen is a humus-loving plant, growing in a humus or peaty 
soil. 
Several fungi attack the Aspen, especially J/elampsora tremule, 
and the petioles are galled by Dzplosis tremule. It is attacked also 
by Eaoascus, Tympanis, Lentinus, Hypholoma, Pholiota, Pleurotus, 
Collybia, Fomes, Polyporus. 
It is galled by Saperda populnea and Eriophyes pustulatum. 
Numerous other insects attack it, such as Saferda carcharias, Mela- 
soma populr, Cladius viminalis (Poplar Hawk Moth), Smerinthus populs, 
Dicranura vinula (Puss Moth), Pemphigus bursarius, P. spirothece, 
Ortho-stylus bilineatus, Phytocorts popul, Pediopsis nassatus, [diocerus 
tremule, I. fulgidus, I. popult, &c. 
