POP ULUS 
5 
Section II. Aigeiros (p. 9). Winter-buds larger than in Leuce, glabrous, viscous but not 
markedly odorous when opening. Petioles markedly flattened laterally, rendering the laminae 
tremulous. Laminae glabrous or rather hairy when young, rarely ciliate, acute to acuminate, 
glandular-serrate. Bracts laciniate, glabrous. Perianth scarcely oblique, crenulate. Stamens about 
8 — 60. Stigmas greenish-yellow, more or less dilated, stouter than in Leuce. Capsules stouter 
than in Leuce , ellipsoid or subglobular. 
Section III. # Tacamahacca (p. 12). Winter-buds and young leaves resinous, especially when 
opening, as large as in Aigeiros. Petioles scarcely flattened laterally. Laminae of the young leaves 
hairy or glabrous below. Bracts laciniate, glabrous. Perianth rather oblique. Stamens about 20 — 30. 
Capsules with slender or stout pedicels. 
Section I. LEUCE 
Leuce Duby Bot. Gall, i, 427 (1828); Ascherson und Graebner Syn. iv, 1 5 et 16 (1908). 
For characters, see page 4. 
Series of Leuce 
Series i. Albae (see below). Winter-buds often obtuse, hairy, not viscous. Laminae white or 
grey with hairs below at least when young ; of the summer-leaves and sucker-leaves permanently 
white below, lobed or toothed. Pedicel hairy. Stigmas linear, greenish-yellow. (Hybrids may 
have pink or purplish stigmas.) 
Series ii. Tremulae (p. 7). Winter-buds acute, glabrous, somewhat viscous but not odorous 
when opening. Petioles more compressed laterally than in Albae , and laminae very tremulous. 
Laminae glabrous or hairy when young, glabrous or almost so at maturity ; of the sucker-leaves grey 
with hairs but not white. Pedicel glabrous. Stigmas purple, stouter than in Albae. 
Series i. Albae 
Albae nobis; Albidae Dode in Mem. Soc. Hist. Nat. Autun xviii, 18 (1905) as a section; Ascherson und 
Graebner Syn. iv, 16 (1908). 
For characters, see above. 
Species and hybrid of Albae 
1. *P. alba (see below). Winter-buds densely pubescent. Laminae of the summer-leaves and 
sucker-leaves palmately lobed, snow-white below. Catkins shorter, appearing later. Bracts not or 
scarcely laciniate. Stigmas filiform. 
2. P. canescens (p. 6). Winter-buds pubescent or subglabrous. Laminae of the summer- 
leaves and sucker-leaves broadly ovate, coarsely or evenly toothed, white below. Catkins longer and 
stouter, appearing earlier. Bracts laciniate. Stigmas narrowly oblong, stouter than in P. alba. 
P. canescens x tvewiula (p. 7). Laminae suborbicular. Stigmas pink to purple. 
I. *POPULUS ALBA. White Poplar. Plates 1, 2 
Popidus alba Gerard Herb. 1301 (1597); Ray Syn. ed. 3, 446 (1724). 
PopulllS alba L. Sp. PI. 1034 (1753)'; Smith FI. Brit. 1079 (1804)!; Willdenow Sp. PI. iv, 802 (1806); 
Berl. Baumz. ed. 2, 287 (1811); P. major Miller Gard. Diet. ed. 8, no. 4 (1768); P. alba var. nivea Aiton Hort. 
Kew. iii, 405 (1789); Wesmael in DC. Prodr. xvi, pt. ii, 324 (1868); P. nivea Willdenow Berl. Baumz. 227 
( 1 796) ; Dode op. cit. 21 (1905); P. alba var. /3 Bieberstein FI. Taur.-Cauc. ii, 421 (1808); P. alba subsp. eu-alba 
Syme Eng. Bot. viii, 192 (1868) excl. t. 1219; P. alba race nivea Ascherson und Graebner Syn. iv, 19 (1908); Rouy 
FI. France xii, 249 (1910). 
leones: — Reichenbach Icon. t. 614, fig. 1270; Hartig Forst. Culturpfl. t. 32. 
Camb. Brit. FI. ii (1913). Plate /. (a) Long shoot, in early summer, (b) Leaf of summer-shoot, under 
side, (e) The same, upper side. Plate 2. (a) Shoot with staminate catkins. ( b ) Staminate flowers (enlarged), 
one with bract. ( c ) Bracts (enlarged) of staminate flowers. (d) Pistillate catkins, early and late stages. 
( e ) Pistillate flowers and bract (enlarged). (/) Ripening ovaries (enlarged), (g) Winter-bud (enlarged), from 
pistillate tree. Staminate catkins from planted tree in Jersey (S. G.). Other parts from planted pistillate tree 
in Cambridge (C. E. M.). 
Exsiccata : — Billot, 3211, as P. canescens. 
