Populus I 78 1 



A large tree, attaining 100 ft. or more in height and 15 ft. in girth. Bark on 

 young stems thin, smooth, grey or whitish ; on older stems breaking on the surface 

 into small roughened dark-coloured rhombic cavities, which ultimately unite together, 

 making the bark towards the base of old trunks deep and longitudinally furrowed. 

 Young branchlets, towards the top of the long shoots, covered with a dense whitish 

 tomentum, which towards their base and on the short shoots diminishes in quantity, 

 the twigs becoming dull grey or shining and glabrescent. Buds ovoid, more or 

 less tomentose, according to their position on the branchlet. Leaves (Plate 408, 

 Fig. 3) of two kinds — on long shoots and on suckers ovate-deltoid, cordate, acute, 

 dark shining green and slightly tomentose above, covered beneath with a thick 

 greyish tomentum ; margin ciliate, with a few triangular teeth, variable in size, and 

 like the rest of the margin irregularly glandular-serrate ; petiole rounded, tomentose. 

 Leaves on the short shoots, suborbicular or broadly ovate, subcordate, obtuse ; 

 margin non-ciliate, with a narrow translucent border, and a few sinuate non-serrate 

 teeth ; dark green, shining and glabrescent above ; lower surface light green, with 

 traces of scattered grey tomentum ; petiole laterally compressed, glabrescent or 

 slightly tomentose. 



Staminate catkins,^ 2^ to 4 in. long ; axis tomentose ; scales obovate, toothed, 

 yellowish brown, fringed with hairs at the apex ; pedicels pilose ; disc oblique, entire 

 in margin, glabrous ; stamens eight to fifteen. Pistillate catkins about i in. long ; 

 with similar scales ; disc pubescent ; ovary glabrous, with four spreading sub-sessile 

 yellowish simple stigmatic lobes.^ Fruiting catkins, 3 to 4 in, long ; capsules glabrous, 

 two-valved. The stigmatic lobes like those of P. alba, are simple and undivided ; 

 whereas in P. tremula, each lobe is deeply scolloped and waved. 



Populus Bogueana, Dode, op. cit. 24 (1905), is a vigorous form of P. canescens, 

 in which the leaves on the long shoots are very large, 5 in. or more in length and 

 breadth ; and appears to be now sold by some nurserymen as P. tomentosa, the 

 white poplar from Peking. A tree of this at Kew, obtained from Simon-Louis in 

 1904, is now about 25 ft. high. Another at Grayswood, obtained from Barbier 

 in 1906, is 15 ft. high and very thriving. There are also small trees with similar 

 large foliage in the Botanic Gardens at Edinburgh and Glasnevin. I found this 

 form wild in the forest of Orleans, where it was growing evidently from vigorous 

 suckers of the typical grey poplar beside it. 



By P. canescens,^ Smith meant the common grey poplar in England, which I 

 have described above. It differs mainly from typical P. alba in the lesser amount of 



1 A tree in the Cambridge Botanic Garden bore monoecious catkins in 1907, the staminate flowers at the base, the 

 pistillate towards the apex. Similar cases are recorded by Penzig, Pfl. Teratologic, ii. 321 (1894), and by Baillon, in Bull. 

 Soc. Linn. Paris, 1897, p. 658. 



2 The eight stigmas, figured by Smith, Eng. Bot. xxiii. t. 1619 (1806), have not been observed by any other botanist, 

 and were probably abnormal. In Eng. Bot. vii. 114, t. 1392 (1840), the number of stigmas is said to be inconstant, but 

 I have found them invariably four. 



3 The grey and white poplars were first distinguished by Lobelius, Icon. PI. seu Stirp. ii. 193 (lS9i)- Their synonymy 

 is much involved, but has been clearly elucidated in an interesting article by Tidestrom, in the American Midland Naturalist, 

 i. 113 (1909), to which the reader interested in such matters is referred. I am not at all certain that Smith clearly understood 

 the distinctions between the two species, as Sowerby's plate of P. alba, t. 1618 (1806), is the leaf of ^ vigorous shoot of 

 P. canescens ; and Smith's statement that P. alia is not uncommon in moist woods (in England) is erroneous, as the latter is 

 never seen in England, except as a planted tree. Most of his description refers to P. alba ; and his specimen in the herbarium 

 of the Linnean Society, London, certainly belongs to this species. 



VII ^ 



