1796 The Trees of Great Britain and Ireland 



produced abundantly from the roots. Root cuttings are as readily propagated as 

 ordinary cuttings. Dubard, in Ann. Sc. Nat. xvii. 147 (1903), gives an elaborate 

 account of the peculiarities of the suckers of this tree. 



This species comprises two distinct forms, one glabrous in all its parts, the other 

 more or less pubescent, described in detail as follows : 



1. Var. typica, Schneider, op. cit. 5 ; Ascherson and Graebner, op. cit. 39. Con- 

 tinental Black Poplar. 



Young branchlets rounded, glabrous, ashy grey in the second year. Buds 

 reddish, viscid, glabrous, closely appressed to the twig at their base, with a sharp 

 apex curving outwards. Leaves on the long shoots (Plate 409, Fig. 11), about 

 3 in. long, and 2 in. broad, cuneate at the base, gradually tapering from about the 

 lower third, where they are widest, towards the long acuminate apex ; glabrous ; 

 dark green above, light green below ; margin with a narrow translucent border, 

 non-ciliate, finely and crenately glandular-serrate ; petiole glabrous, laterally com- 

 pressed. On the short shoots the leaves are smaller, broader at the base, which 

 is often less cuneate, and truncate or rounded ; and similar leaves often occur on old 

 trees even on the long shoots. 



Catkins about \\ in. long, with early deciduous scales, which are broadly 

 obovate, and divided into numerous irregular, linear entire or lanceolate toothed 

 lobes ; axis glabrous. Staminate flowers sub-sessile ; stamens twenty to thirty on 

 an oblique concave non-ciliate glabrous disc, which is slightly waved and upturned 

 in margin ; filaments white, thread-like, as long as the deep red anthers. Pistillate 

 flowers shortly stalked ; ovary glabrous, globose, in a cup-like glabrous disc ; stigmas 

 two, dilated, crenate in margin, closely appressed at first to the sides of the upper 

 part of the ovary. Capsules two-valved, glabrous, on long pedicels. 



2. Var. betulifolia, Torrey, Fl. New York, ii. 216 (1843) ; Skan, in Bot. Mag. 

 t. 8298 (in part 1 ) (1910) ; Schneider, Laubholzkunde, ii. 870 (191 2). English Black 

 Poplar. 



Var. viridis, 2 Lindley, ex Loudon, Arb. et Frut. Brit. iii. 1652 (1838). 



Var. betulcefolia, Wesmael, in De Candolle, Prod. xvi. 2, p. 328 (1868). 



Var. hudsonica, Schneider, Laubholzkunde, i. 5 (1904); Ascherson and Graebner, Syn. Mitteleurop. 



Fl. iv. 39 (1908). 

 Populus nigra, Michaux, Fl. Bor. Am. ii. 244 (1803) (not Linnaeus). 

 Populus hudsonica, Michaux f., Hist. Arb. Amer. iii. 293, t. 10, fig. 1 (1813), and N. Amtr. 



Sylva, ii. 114, t. 96, fig. 1 (1819). 

 Populus betulifolia, Pursh, Fl. Amer. Sept. ii. 619 (1814); Loudon, Arb. et Frut. Brit. iii. 



1656 (1838); Dode, in Mim. Soc. Hist. Nat. Autun, xviii. 48 (1905). 

 Populus nigra, Vaillantiana, and Muelleriana, Dode, in Mini. Soc. Hist. Nat. Autun, xviii. 48 



(1905)- 



Young branchlets rounded, covered with a dense short pubescence, orange or 

 yellow in the second year. Buds greenish, tinged with brown, viscid, otherwise as 



' The female catkins figured show ovaries with three stigmas, and were taken from a hybrid tree (P. Lloydii) growing 

 near Turnham Green station. Cf. p. 1831, note 1. 



J Lindley's specimen in the Cambridge Herbarium is a vigorous branch from a young tree of P. nigra, var. betulifolia. 

 This is confirmed by a tree labelled var. viridis in the Cambridge Botanic Garden. Loudon's description of this variety, 

 " leaves of a brighter green than the species," is inadequate ; and the name var. viridis, though older than that of var. 

 betulifolia, cannot be used. Mackie, in Loudon, Gard. Mag. xiii. 230 (1837), says that var. viridis was discovered at Beatings, 

 near Woodbridge, and had been grown in his nursery at Norwich for twenty years. 



