212. POPULUS 



true balsam poplar is an erect-branched tree now rarely seen in this country, 

 where nearly all poplars so-called are the closely allied, broader-topped P. 

 candicans. It produces suckers freely, which afford the best means of increase. 

 The great charm of this tree is the balsamic odour of its unfolding leaves in 

 spring which fills the air around. It is the type of a group of poplars with 

 the same quality more or less developed, but it is not so valuable a tree as 

 its W. American ally, P. trichocarpa. The leaves on vigorous suckers are 

 occasionally of enormous size. I have measured one 13 ins. long, and 10 ins. 

 wide. Only the male plant appears to be in cultivation. 



P. BEROLINENSIS, Dippel. BERLIN POPLAR. 

 (P. certinensis, Hort.) 



A supposed hybrid between P. laurifolia (female) and the Lombardy poplar, 

 said by Koch (Dendrologie, ii. p. 497) to have first appeared in the Botanic 

 Garden of Berlin. Although described nearly fifty years ago, it has spread 

 but little in cultivation, although a handsome tree of slender columnar shape. 

 Its young shoots are downy, slightly angled. Leaves broadly ovate and 

 rounded at the base, or somewhat diamond-shaped and wedge-shaped at the 

 base, slender-pointed, finely toothed like P. laurifolia ; \\ to 4 ins. long ; 

 upper surface bright green, lower one pale, scarcely whitish ; both sides soon 

 quite smooth ; stalk slender, downy at first, f to i^ ins. long. This tree 

 thrives remarkably well in the vicinity of Berlin, where it originated. Some 

 years ago, I saw some particularly handsome examples in Mr Spath's nursery 

 near that city. It is strongly recommended by him for street-planting, but is 

 perhaps better adapted for the cold winters and hot summers of middle 

 Europe than for this country. The larger of two trees planted at Kew in 1880 

 is now 57 ft. high, and 3 ft. 3 ins. in girth ; these trees are males (generally 

 known as " P. certinensis "), and for this country appear to be preferable to the 

 female. 



P. CANDICANS, Aiton. BALM OF GILEAD, ONTARIO POPLAR. 



(P. ontariensis, Desfontaines.) 



This is the tree generally called balsam poplar in Britain, and much more 

 common in gardens than the true P. balsamifera (q.v.}. It is, no doubt, very 

 nearly allied to that tree, and Sargent (Trees of N. America, p. 159) only 

 admits it as a form. Most other authorities now regard it as a species, as did 

 Aiton and Loudon. It has the general character of P. balsamifera, the same 

 sucker-producing habit, balsamic resin-covered buds, and odoriferous young 

 foliage ; also the whitish under-surface of the leaf conspicuously netted over 

 with veins. But it differs in the following respects : its branches are more 

 spreading than in P. balsamifera, and it thus forms a broader, more open 

 crown ; its leaves are broader and more generally heart-shaped, more downy 

 beneath, and ciliate ; and its leaf-stalks and young shoots are downy. It has 

 been in cultivation since 1773, but there is considerable doubt as to its origin, 

 the general opinion being that it is N. American, where, however, there 

 appears to be some difficulty in distinguishing between escapes from cultiva- 

 tion and genuinely indigenous specimens. The authors of the last edition of 

 Gray's Manual of Botany put it down as " introduced, perhaps of Asiatic 

 origin." (In this, possibly, they have in mind P. tristis see below.) For 

 cultivation in this country P. candicans is a better tree than P. balsamifera, 

 but not so good as P. trichocarpa. It may often be seen in out of the way 

 places in London suburbs producing a swarm of suckers, and scenting the air 

 around on moist spring days. 



