1832 The Trees of Great Britain and Ireland 



in a shallow cup-shaped crenate disc. Fruiting catkins, 4 in. long ; capsule two- 

 valved, glabrous, on a in. long pedicel. 



This species is a native of the Rocky Mountain region of North America, 

 usually growing on the banks of streams between 5000 and 10,000 ft. It occurs as 

 far north as south-western Assiniboia, extending southward through the Black Hills 

 of Dakota, Montana, eastern Idaho, Wyoming, Utah, Colorado, 1 to central Nevada, 

 Arizona, and New Mexico. 



It is readily distinguishable amongst the balsam poplars by its willow-like leaves, 

 which scarcely show any whitish tint beneath. 



It was introduced into cultivation by Spath 2 of Berlin, who received young plants 

 from Colorado in 1893. I* forms at Kew small trees of spreading irregular habit, and 

 may be looked upon as rather a shrub than a tree in this country. (A. H.) 



POPULUS BALSAMIFERA, Balsam Poplar 



Populus balsamifera, Linnaeus, Sp. PL 1034 (excl. syn. Catesby et Gmelin) (1753) ; Loudon, Arb. et 

 Prut. Brit. iii. 1673 (in part) (1838); Sargent, Silva N. Amer. ix. 167, t. 490 (1896), and 

 Trees N. Amer. 157 (1905); Schneider, Laubholzkundc, i. 14 (1904); Dode, in Mem. Soc. 

 Hist. Nat. Autun, xviii. 62 (1905); Gombocz, in Math. Termes. Kozl. xxx. 108 (191 1). 



Populus Michauxi, Dode, op. cit. 62 (1905). 



A tree, attaining in America 100 ft. in height and 20 ft. in girth. Bark at first 

 smooth, light reddish brown ; on old trunks deeply divided into broad rounded ridges, 

 Young branchlets terete, without projecting ridges, glabrous. Buds elongated, sharp- 

 pointed, exuding a yellowish strong-smelling resin. Leaves (Plate 410, Fig. 27) 

 on long shoots averaging 4 in. long and 2 in. broad, ovate, rounded at the 

 base, narrowing towards the apex, which is often abruptly acuminate, glabrous on 

 both surfaces, whitish and often tinged with rusty red beneath ; margin minutely 

 and sparsely ciliate, with crenate serrations, ending in short incurved glandular 

 points ; lateral nerves about eight pairs, each of the lowest pair giving off at its origin 

 usually one secondary nerve, making with the midrib the base of the blade pseudo- 

 five-palminerved ; petiole quadrangular, channelled above, with a minute scattered 

 pubescence. Leaves on short shoots smaller, broader in proportion to their length. 



Staminate catkins about 3 in. long ; axis with a few scattered hairs ; pedicels long 

 and similarly pubescent ; scales broadly obovate, often irregularly three-lobed at the 

 apex, with numerous short thread-like divisions ; stamens about twenty on an 

 oblique crenate deep saucer-shaped glabrous disc. Pistillate catkins : disc cup- 

 shaped ; ovary ovoid, two-lobed, with two nearly sessile large oblique dilated 

 crenulate stigmas. Fruiting catkins 5 in. long ; capsule ovoid, curved at the apex, 

 two-valved, on a slender pedicel about ^ in. long. 



This species, extending over a wide area in North America, is probably vari- 

 able ; and may hybridise with P. candicans. The form distinguished by Dode as 



1 F. von Holdt, of Arvada, Colorado, in Mitt. Deut. Deitd. Ges., 1912, pp. 118, 119, describes this poplar in its native 

 home, and gives a fine photograph of it growing on the edge of a mountain lake. 

 s Catalogue, No. 91, p. 49 (1893- 1894). 



