220 POPULUS 



ovate ; from ^ to 2 ins. wide on the short lateral twigs, as much as 4 ins. wide 

 on vigorous long shoots ; apex pointed, base rounded or straight ; prominently 

 toothed, t-he teeth being few, large (often & to in. deep), blunt, and somewhat 

 incurved ; margin thickened ; more or less woolly when young, becoming 

 quite smooth by autumn, or with remains of the down beneath towards the 

 base near the leaf-stalk ; stalk very slender, usually smooth, to T\ ins. long, 

 two-edged. On the leaves of vigorous shoots there is a pair of glands where 

 it joins the blade. Male catkins grey, 2 to 4 ins. long, produced in February. 



Native of Europe (including Britain), eastward to Asia Minor and the 

 Caucasus. It is more common in the north of Britain than the south. The 

 best known attribute to the aspen is the perpetual quiver of the leaf. " To 

 tremble like an aspen leaf" is a phrase whose use goes back to Spenser's time, 

 perhaps long before. This movement is seen in other poplars with com- 

 pressed leaf-stalks, but is never so marked as in this. In the south of England 

 the aspen does not succeed as well as in the north, but is worth planting for 

 its interest. A curious superstition prevailed in the Scottish Highlands 

 (perhaps does so now) that the cross on which the Saviour was crucified was 

 made of the wood of this tree, and it was, in consequence, held in abhorrence. 

 In the north of England it is (or was, thirty years ago) regarded by peasant 

 women and children with a feeling of dislike akin to fear, probably owing to 

 some similar legend. 



The aspen is only likely to be confounded with two other poplars the 

 one, P. tremuloides, an American species distinguished by the pale yellowish 

 bark of young trunks and main branches, and by the smaller type of leaf, being 

 very finely and evenly toothed, and. furnished with hairs on the margin when 

 young, but otherwise smooth ; the other, P. canescens, is easily distinguished 

 by the whitish wool on the under-surface of the leaf, and also pale bark of the 

 young trunk. 



Var. PENDULA, Loudon. Weeping Aspen. A male form with stiff, pendulous 

 branches, well known as a lawn tree grafted on P. canescens. It is valued for 

 its great wealth of grey purplish catkins produced in February, and is one of 

 the most conspicuous and beautiful of early-flowering trees. 



Var. PURPUREA. Leaves with a purplish tinge, not very marked. A 

 female tree. 



Var. VILLOSA, Syme (P. villosa, Lang]. Downy Aspen. A form with 

 shoots hairy until the second year. Leaves also more persistently downy than 

 in the type. The variety does not appear to be common in cultivation. 



P. TREMULOIDES, Michaux. AMERICAN ASPEN. 



A tree up to 100 ft. high in a wild state, but never even half that size in 

 this country ; trunk slender, paler than in P. tremula when young ; young 

 shoots reddish brown, smooth. Leaves I to 2^ ins. long and wide, very 

 broadly ovate or roundish, with a short, abrupt apex, and a broad, rounded or 

 nearly straight base ; very finely toothed, and furnished with fine hairs on the 

 margin ; dark glossy green above, pale and dull beneath, smooth on both 

 sides ; stalk slender, two-edged, I to 2^ ins. long. Catkins 2 to 2^ ins. long, 

 more slender than in P. tremula. 



Native of N. America, and found on both sides of the Continent. Jepson 

 observes that it is the most widely distributed of N. American forest trees, 

 and is the only Californian tree that reaches the Arctic Circle. It is often 

 confused in gardens with the Old World P. tremula, from which it differs in 

 characters pointed out under that species. According to Aiton, it was intro- 

 duced in 1812, but there is some doubt as to this ; a poplar grown under the 

 name of P. graeca, but identical with P. tremuloides, is said to have been culti- 

 vated in 1779. P. tremuloides has never succeeded very well in this country. 



