6 
POP ULUS 
Tree, up to about 25 m. high in this country, suckering freely. Bark brownish-grey. Branches 
ascending at a rather wide angle. Winter-twigs more hairy, more slender, and less knotted than in 
P. canescens. Winter-buds hairy. Summer-buds and summer-shoots covered with snow-white hairs. 
Petioles shorter than the laminae. Laminae more or less suborbicular, sublobed, densely hairy below, 
somewhat glabrescent ; of the terminal leaves of the summer shoots and of the suckers somewhat 
cordate, deeply and palmately lobed, lobes triangular, snow-white below, dark green above ; of the 
lower leaves of the summer-shoots more or less suborbicular and sublobed. Catkins mid-March to late 
March. Staminate catkins rare (only seen from Jersey), shorter and more slender than in P. canescens. 
Bracts irregularly and rather acutely crenate. Stamens about 8. Pistillate catkins about i'5 to 2'o cm. 
long. Bracts not deeply divided. Stigmas greenish-yellow, linear, slender, spreading. Capsule about 
twice as long as broad. 
Many of the records of “ P. alba ” in this country refer to P. canescens. The two species are, however, quite distinct, 
and easily recognisable in early spring by the shape of the bracts, and in summer by the shape of the laminae of the 
summer-shoots and of the suckers. 
P. alba is always, we believe, a planted tree in this country and, indeed, in western Europe generally. Rouy ( loc . cit .) 
questions its being indigenous in Corsica. The planted tree is almost invariably pistillate. 
Suburban gardens, parks, plantations, and very rarely by stream-sides and in woods. Not uncommon in the 
Channel Isles, in the lowlands of southern England and Scotland, becoming rare westwards and northwards ; 
planted at 300 m. in Derbyshire; Ireland. 
Western Europe (not indigenous) ; central Europe (doubtfully indigenous) ; eastern and south-eastern Europe 
to Turkestan. An allied form or species occurs eastwards to central China. 
2. POPULUS CANESCENS. Grey Poplar. Plates 3, 4; 5 
P. alba foliis minoribus Johnson in Gerard Herb. ed. 2, 1487 (1636); P. alba “alia” Ray Syn. ed. 3, 446, 
no. 2 (1724). 
Populus canescens Smith FI. Brit. 1080 (1804)!; Willdenow Sp. PI. 802 (1806); Bert. Baumz. ed. 2, 
287 (1811); P. alba Miller Card. Diet. ed. 8, no. 1 (1768); Willdenow Berl. Baumz. 227 (1796); Bieberstein FI. 
Taur.-Cauc. ii, 421 (1808) excluding var. /3 ; Fries FI. Scan. 147 (1835)!; non L. ; P. alba var. canescens Aiton 
Hort. Kew. iii, 405 (1789); P- alba subsp. canescens 
Syme Eng. Bot. viii, 194 (1868) ; P. alba var. genuina 
Wesmael in DC. Prodr. xvi, pt. ii, 324 (1868); P. 
alba race genuina Ascherson und Graebner Syn. iv, 
22 (1908). 
leones : — Smith Eng. Bot. t. 1618, as P. alba\ 
t. 1619, excluding the stigmas which are abnormal ; 
FI. Dan. t. 2182, as P. alba ; Hartig Forst. Culturpfl. 
t- 33 - 
Camb. Brit. FI. ii (1913). Plate j. (a) Long 
shoot, in early summer. ( b ) Long shoot, in summer, 
from a young tree. Plate 4. (a) Shoot with stami- 
nate catkins, (b) Staminate flowers, one with bract. 
(c) Staminate flower with bract (enlarged). ( d) Pis- 
tillate catkins (early and later stages). ( e ) Pistillate 
flowers and bracts. (/) Ripening ovaries (enlarged). 
( g ) Leaf-bud (enlarged), from staminate tree. (//) Leaf- 
bud (enlarged), from pistillate tree. (#) Long shoot 
in summer from a young tree. Huntingdonshire 
(E. W. H.). 
Exsiccata : — Billot, 2534; Fries, xiii, 69, as P. 
alba. 
Tree, growing to a height of 30 or 35 m., 
suckering freely. Bark brownish-grey. Bran- 
ches wide-spreading ; of old trees descending. 
Twigs thick and knotted. Winter-buds pubes- 
cent to glabrescent, obtuse. Summer-buds and 
summer-shoots hairy, often white with hairs. 
Petioles about as long as the laminae. Laminae 
broadly ovate-orbicular, truncate at the base, 
with a few large blunt teeth, obtuse, white to grey 
Map 1. Distribution of Populus canescens in England and Wales 
P. canescens is probably indigenous in the counties which are shaded, 
doubtfully indigenous in the counties which are marked with a “ ? ”, 
and not indigenous in the remaining counties. 
