1410 



POPULUS 



POPULUS 



the blade and commonly with 2 or 3 glands at the top, 

 the stipules small and falling earl}*: catkins long and 

 loosely flowered : fruit an ovoid acute capsule. Gen- 

 erally distributed from Quebec to the Rocky Mts. and 



1913. Populus deltoides, var. Carolinensis (X /^). 



south to Fla., mostly in moist lands or along the moun- 

 tains. S.S. 9:494, 495. — Variable. Some of the forms 

 are fairly distinct in foliage and aspect, and they ap- 

 pear to be associated with particular horticultural 

 names in the nurseries. Some of the most ornamen- 

 tal specimens of Cottonwood are those with reddish 

 leaf-stalks and midribs. Taking all things into con- 

 sideration, the Cottonwood is probably the best of the 

 Poplars for general ornamental planting. It grows 

 rapidly and in almost every soil, and yet it possesses 

 elements of strength and durability which most of the 

 Poplars lack. Its foliage is always bright and glossy, 

 and the constant movement of the broad rich green 

 leaves gives it an air of cheeriness which few trees 

 possess. The tree has been much used upon the 

 prairies and in nearly all western towns, much too abun- 

 dantly for good landscape effects. The rapid growth of 

 the tree gives a feeling of 

 luxuriance to plantations 

 even when most other 

 trees appear to be weak 

 or starved. The Cotton- 

 wood thrives best on 

 rather low lands, and yet 

 it is generally an admir- 

 able tree upon high and 

 dry areas. There is a 

 golden-leaved form of 

 the Cottonwood known 

 as variety Van Geertii 

 or var. a urea. This is 

 one of the best of yellow- 

 leaved trees, and gener- 

 ally holds its color 

 throughout the season. 

 Like all trees of this un- 

 usual character, it should 

 be used cautiously, and 

 the best effects are ob- 

 tained when it is planted 

 against a group of trees 

 so as to appear as if 

 naturally proj ecting 

 from the other foliage. 

 Var. Carolin6nsi8 (P. Carolinfnsis, Willd. P. Caro- 

 Ihifi iii\<\ Citron tiiini(i,'iiort.). Carolina Poplar. Fig. 

 IQl.'t. A very distinct tree in habit of growth, makins; a 

 straight upritrht or pyramidal head: Ivs. usually less 

 distinctly deltoid ami more gradually taper -pointed 



1914. Populus nierra, var. Italica — 

 Lombardy Poplar (X ^3). 



than in P. deltoides. Native.— The Carolina Poplar 13 

 much planted, and nurserymen consider it to he dis- 

 tinct from the Cottonwood. It differs in strict, straight 

 appearance, and it is a most vigorous grower. It is 

 much planted in Europe, where it is known as the 

 Swiss Poplar. Its botanical position needs to be inves- 

 tigated. 



6. laurifdlia, Ledeb. (P. balsamifera, var. laurifolia, 

 Wesm. P. Certinensis, P. Petr6vski, P. JBereolen.sts, 

 Hort.). Certinensis Poplar. Fig. 1912. A very rapid- 

 growing and hardy tree, with a strong central leader and 

 a very heavy, dense foliage. Dift'ers from P. deltoides 

 as follows: Ivs. broad-ovate in outline, with a rounded 

 or tapering base and rather short point at the apex; the 

 margin rather closely-toothed, wavy; leaf-stalk com- 

 paratively short, only moderately flattened, glandlfss at 

 the top; stipules present and conspicuous: bud long: 

 shoots slightly hairy. Siberia. — The foliage on the old 

 wood or upon slow-growing shoots is very unlike that 

 upon the vigorous branches, and is almost identical 

 with that of the Balsam Poplar, being broadly oval, with 

 finely serrate margins, and whitish beneath. The twigs, 

 also, are cylindrical. But the strong shoots are strongly 

 angled or grooved and the foliage is much like that of 

 the native Cottonwood but darker; and the growth is 

 more close and erect. The sketch in Fig. 1912 distin- 

 guishes the leaves. The Certinensis Poplar is a more 

 rugged tree than the Cottonwood, with healthier foliage 

 in the presence of leaf-rust, and its wood is said to be 

 valuable. It is now much planted in the Northwest, 

 and deserves to be widely distributed. Its effect in the 

 landscape is considerably unlike that of the Cottonwood. 

 Its leaves stand out more horizontally, while those of 

 the Cottonwood hang loosely and often vertically and 

 therefore give the tree-top a heavier look. The terminal 

 spray of the two is particularly distinguishable in this 

 regard. The leaves of Certinensis upon the strong, erect 

 shoots stand almost at right angles to the shoot, and, 

 at some distance, therefore, present only their ruffled 

 edges to the eye, producing a unique and picturesque 

 effect. 



cc. Leaves relatively small, mostly as broad as, or 

 broader than, long. 



7. nigra, Linn. Black Poplar. Tree of medium 

 to large size, with leaves somewhat resembling those of 

 the Cottonwood, but generally smaller and much less 



1915. Populus Tremula (X 14). 



deeply toothed, shorter in proportion to their width and 

 often with a tapering or rounded base; leaf -stalk 

 much flattened, so that the foliage moves freely in the 

 wind. Eu., Siberia. — The tree usually has a pyra- 

 mi<lal habit of growth and a dark cast to the foliage. 

 It is a less lustrous tree than the Cottonwood and grows 

 more slowly. Specimens were found escaped along the 

 Hudson by Mieliaux, who thought it an American spe- 

 cies and published it early in the century as Populxs 

 Eudsonica. Pursh, in 1814, published it again as the 

 "birch-leaved Poplar," Po^;((/!(.s- hettilifolia, from trees 

 found near Lake Ontario. Although it was found half 

 wild in New York about a century ago, it does not 

 appear to have increased itself in America, for it is 



