212 TREES AND SHRUBS. 



country. It has thick, oblong-ovate, acute or acuminate glabrous 

 rate with numerous teeth, and often from 1 to 1.2 decimetres long, 

 veins and petioles. The fact that this tree is not always perfectly hardy in England would indicate its southern origin. 



Aiton's specimens, however, of Populus angulata are preserved in the British Museum, and well represent the Cottonwood of 

 the Ohio valley, the lower Mississippi valley, and the south Atlantic and Gulf States, where the younger Michaux found what 

 he considered Populus angulata. This southern tree is distinguished from the northern Cottonwood by the deciduous hairs which 

 cover the upper surface of the young leaves and by the pubescence on their lower surface, which is more or less present during 

 the season, especially on the midribs and veins. The leaves are sometimes rather larger than those of the northern tree ; but 

 this is perhaps due to the rich soil of the southern river bottoms, and vigorous branches are as often angular on northern as on 

 southern trees ; I suggest for the southern tree the name of — 

 Populus deltoidea, var. angulata, n. var. 

 Populus angulata, Aiton, Hort. Kew. iii. 407 (1789). — Michaux f. Hist. Arb. Am. iii. 302, t. 12. — Chapman, Fl. 431. 

 Populus deltoidea, Sargent, Silva N. Am. ix. 179 (in so far as relates to-the southern states, not Marshall) (1896). 

 This is the common Cottonwood of all the regions south of the Potomac and Ohio Rivers, ranging to the southwest as far a 

 least as the neighborhood of San Antonio, Texas. It is common on the banks of the Potomac River in Washington, where Tide 

 strom (Clusium marianum, 17) says that he has observed Populus virginiana, although he says nothing about the pjibescence whic I 

 is well developed on these Potomac trees. Populus virginiana Fougeroux is an older name than Populus angulata, but Fougerour 

 gives no real description of his species, and it is impossible to determine his tree, although his name has been taken up by boti 

 Dode and Tidestrom. Of Tidestrom's specimens in the Herbarium of the Arnold Arboretum, No. 4699 from Glen Echo, Maryland, 

 in the valley of the Potomac River, has the pubescent leaves of P. deltoidea var. angulata, but No. 4556 from the same locality 

 and No. 4694 from High Island in the valley of the Potomac have the leaves perfectly glabrous. 



Populus deltoidea (canadensis) of German dendrologists (not P. canadensis of Michaux) (see C. K. Schneider, ///. Handb. Laub- 

 holzk. iii. 7, f . 1, d-f, f. 3, o-p 1 ) is another tree which we have been unable to find growing naturally in any part of the United 

 States. The leaves are described as glabrous on the margins, and at the base of the shoots they are cuneate. The ovaries are 

 three-celled with spreading stigmas. The female flowers of Populus monilifera as cultivated in Germany are described as with 

 a pointed two-celled ovary and erect stigmas, and this tree is considered distinct from P. deltoidea (see Schneider ///. Handb 

 Laubholzk. i. 7, f. 1, a-c, f. 3, n-n 2 ). In all the flowers of wild trees we have been able to examine the ovaries are three- or 

 four-celled with spreading stigmas ; and in all of eastern North America we have been able to find only one Cottonwood with 

 leaves which are truncate or subcordate at the base, glabrous in the north and pubescent in the south. 



The Poplar which has for several years been largely planted as a street tree in the United States is believed to be a hybrid of 

 European origin between the northern Cottonwood of the United States and the so-called Lombardy Poplar. It is a tree with 

 rather a narrow head of semierect branches and leaves which are cuneiform or rounded at the base. Only the staminate tree is 

 known. The name of this hybrid appears to be — 



Populus Eugenei, Hort. ex Dode, Extr. Monog. lned. Populus, 46 (1905). — C. K. Schneider, III. Handb. Laubholzk. i. 9. 

 Populus canadensis Eugenei, Schelle, Beissner, Schelle & Zabel, Handb. Laubholzk. 16 (1903). 



Populus Eugenei sprang up many years ago in the nurseries of Simon-Louis Freres at Plantieres near Metz, in Alsace. It is 

 hardly possible that all the cultivated trees of this hybrid are descended from the single individual at Plantieres, and it is prob- 

 able that other individuals of the same parentage varying somewhat among themselves in habit and foliage have been propagated 

 by nurserymen. Poplar trees apparently of the same origin have been much planted in Europe, where they are generally known 

 as the Swiss Poplar and as the Black Italian Poplar, and it is probably this tree which Lamarck described under the name of 

 Populus nigra helvetica (Diet. v. 234 [1834]). In the United States this hybrid is usually called Canadian Poplar or Cottonwood. 



Two other hybrid Poplars may be described as — 

 Populus Jackii, n. hyb. 



(Populus balsamifera X deltoidea.) 



Leaves ovate, gradually narrowed, long-pointed and acuminate at the apex, rounded, slightly cordate or occasionally abruptly 

 cuneate at the base, finely erenately serrate, glabrous, dark green and lustrous on the upper surface, pale and lustrous on the 

 lower surface, from 7 to 8 centimetres long and from 6 to 7 centimetres wide ; on vigorous shoots usually cordate at the base 

 silvery white on the lower surface and often 1.5 decimetres long and from 1.2 to 1.4 decimetres wide ; petioles slender, com- 

 pressed laterally, from 4 to 5 centimetres in length. Flowers and fruits not collected. 

 A tree, with slender slightly angled branchlets and narrow acuminate resinous buds. 



A single large tree on Nuns' Island, at the mouth of the Chateaugay River, Province of Quebec, J. G. Jack, August 24, 1889, 

 August 4 and 20, 1902, August 11, 1909, September 16, 1911; also a small tree on the south bank of the St. Lawrence River at 

 Beauharnois, Province of Quebec, /. G. Jack, August 9, 1908. These trees show the influence of Populus balsamea in the pale 

 ° r /iv e 7 J Un , SUrfaCe ° f the finely Se " ate leaves and m the buds > and the influence of P. deltoidea in the broad leaves. It is 

 established in the Arnold Arboretum. 



Populus Andrewsh, n. hyb. 



(Populus acuminata X Sargentii.) 

 JTT °l )1 K 0ng ' O : a ^ B^^My «* abruptly long-pointed and acuminate at the apex, rounded or occasionally abruptly cuneate 



the broad base, finely erenately serrate except at the very apex, thin, bright green and lustrous above, rather paler below, from 



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