SALICACEZ. 153 
SILVA OF NORTH AMERICA. 
Populus is the oldest type of dicotyledonous plants yet identified, and its traces, with those of 
Sequoias, Pines, and Cycads, have been found in the lower cretaceous rocks of Greenland. It was 
common on the mid-continental plateau of North America during cretaceous times, and in Europe and 
North America during the tertiary epoch, and predominated in the miocene of Europe, the remains of 
twenty-eight species of that period having been described.! 
The wood of Populus contains numerous small scattered open ducts. That of many of the species 
is suitable for paper-making,? and is used in large quantities in the United States and Canada for this 
purpose, and several species furnish wood that is employed in construction and in the manufacture 
of small articles, the most valuable timber-trees of the genus being the North American Populus del- 
toidea, Populus heterophylla, and Populus trichocarpa, the European and Asiatic Populus nigra,’ 
This large tree is distributed from northwestern India and west- 
ern Thibet through western Siberia and Manchuria to Kamtschatka 
and to Saghalin, and northern Japan, where in southern Yezo it is 
sometimes a hundred feet in height, with a trunk three or four feet 
in diameter. 
The second of these Asiatic Poplars appears to be chiefly confined 
to the Altai region of southern Siberia. It is: — 
Populus laurifolia, Ledebour, Fl. Alt. iv. 297 (1833) ; Icon. Fi. 
Ross. t. 479; Fil. Ross. iii. 629. — Fischer, Gartenzeit. ix. 404. — 
Spach, Ann. Sci. Nat. sér. 2, xv. 33 (Revisio Populorum) ; Hist. 
Vég. x. 394.—Dippel, Handb. Laubholzk. ii. 209.— Koehne, 
Deutsche Dendr. 85. 
Populus balsamifera viminalis, Loudon, Arb. Brit. iii. 1673 
(1838).— Wesmael, De Candolle Prodr. xvi. pt. ii. 330 ; Mém. 
Soc. Sci. Hainaut, sér. 3, iii. 247, t. 7, £. 2. 
Populus longifolia, Fischer, 1. c. 403 (1841). 
Populus balsamifera, 8 laurifolia, Wesmael, De Candolle Prodr. 
i. c. (1868) ; Mém. Soc. Sci. Hainaut, 1. c. 246, t. 7, £. 1. 
This is a tree with angled branches and rather narrow leaves. 
In a wild state it rarely grows, it is said, more than from thirty to 
forty feet in height. It is often planted as a street tree in the 
towns of northeastern Russia. 
Many forms or perhaps hybrids of this tree, of Populus suaveolens 
and of Populus balsamifera, are cultivated in western Europe and 
have been introduced into the United States. One of them, under the 
name of Populus Certinensis, has shown remarkable power to resist 
drought and cold, and is considered one of the most valuable shade- 
trees in the region between the Great Lakes and the Rocky Moun- 
tains and northward. (See Green, Bull. Minnesota Agric. Exper. 
Stat. No. 9, 39 [Russian Willows and Poplars].) 
1 Newberry, Ann. Lyc. N. Y. ix. 60 (Extinct Floras of North 
America). — Lesquereux, Rep. U. S. Geolog. Surv. vii. 172, t. 22, 
f. 8-13, t. 23, t. 24, t. 62, f. 5, t. 64, £5; viii. 157, t. 30, f. 1-8, 
t. 38, f. 9-11 (Fossil Fl. W. Territories, ii., iii.) ; Mem. Mus. Comp. 
Zool. vi. pt. ii. 11, t. 8, f. 1-8 (Fossil Plants of the Auriferous Gravel 
Deposits of the Sierra Nevada). —Saporta, Origine Paléontologique 
des Arbres, 182. — Zittel, Handb. Paleontolog. ii. 458. 
? Stonhill, Rattray & Mull Forestry and Forest Products, 437 
(History of Wood Paper). —Spons, Encyclopedia of the Industrial 
Arts, Manufactures, and Raw Commercial Products, ii. 1493. 
* Linneus, Spec. 1034 (1753).— Willdenow, Spec. iv. pt. ii. 
804. — De Candolle, Lamarck Fl. Frang. ed. 3, iii. 299. — Smith & 
Sowerby, English Bot. xxvii. t. 1910.— Reichenbach, Icon. Fi. 
German. xi. 30, t. 619.— Hartig, Forst. Culturpfl. Deutschl. 435, t. 
35.— Willkomm & Lange, Prodr. Fl. Hispan. i. 233. — Parlatore, 
Fi. Ital. iv. 288.— Wesmael, De Candolle Prodr. l. v. 327 ; Mém. 
Soc. Sci. Hainaut, 1. c. 238, t. 19, f. 1. — Boissier, Fl. Orient. iv. 1194. 
Populus versicolor, Salisbury, Prodr. 395 (1796). 
Populus Neapolitana, Tenore, Fl. Nap. v. 279 (1836). 
Populus caudina, Tenore, J. v. 280 (1836). 
Populus nigra is a large tree of rapid growth, with erect spread- 
ing branches ; it is distributed from central Europe to northern 
Africa, Persia, and southern Siberia, and through cultivation has 
become naturalized in Great Britain and southern Scandinavia 
(Bentham, Ill. Handb. Brit. Fl. ii. 770), and sparingly in North 
America, where the younger Michaux found it growing spontane- 
ously on the banks of the Hudson River above Albany (Populus 
Hudsonica, Michaux f. Hist. Arb. Am. iii. 293, t. 10 [1813]), and 
Pursh on the shores of the Hudson and of Lake Ontario (Populus 
betultfolia, Pursh, Fl. Am. Sept. ii. 619 [1814]). It now grows on 
a small island in the Delaware River near Easton, Pennsylvania, 
where it was found by Professor Thomas C. Porter ; and in the 
neighborhood of cities it occasionally occurs along the borders of 
highways apparently as an escape from cultivation. 
The wood of Populus nigra, which is soft and splits readily, is 
largely used in central Europe in making packing-cases, trays, 
bowls, dishes, and the soles of shoes. The bark is used in tanning 
leather, and that from the base of old trunks for the floats of fish- 
nets. The vigorous young shoots sometimes replace those of the 
Willow in coarse baskets ; the hairs which surround the seeds have 
been made into cloth and utilized as a substitute for cotton in wad- 
ding garments ; and extracts of the balsamic buds are employed 
domestically in the treatment of nervous diseases. (See Loudon, 
Arb. Brit. iii. 1652.) 
The most distinct in habit and the most widely spread through 
cultivation of all the Poplars is the tree with fastigiate branches 
known in the United States as the Lombardy Poplar and now usu- 
ally considered a variety of Populus nigra. It is :— 
Populus nigra Italica, Du Roi, Harbk. Baumz. ii. 141 (1772). 
Populus Italica, Moench, Béume Weiss. 79 (1785). 
Populus dilatata, Aiton, Hort. Kew. iii. 406 (1789). — Willde- 
now, J. c.— Hayne, Arzn. xiii. t. 46. 
Populus pyramidata, Moench, Meth. 339 (1794). 
Populus pyramidalis, Borkhausen, Handb. Forstbot. i. 541 
(1800).— Spach, Hist. Vég. x. 388.— Koch, Syn. Fl. German. 
ed. 2, 760. — Wilkomm & Lange, J. c. 233. — Boissier, /. c. 
Populus fastigiata, Poiret, Lam. Dict. v. 235 (1804).— Des- 
fontaines, Hist. Arb. ii. 465.— Du Mont de Courset, Bot. Cult. 
ed. 2, vi. 399. 
Populus nigra, B pyramidalis, Spach, Ann. Sci. Nat. l.c. 31 
(1841). — Parlatore, J. c. 289.— Wesmael, De Candolle Prodr. 
l. c. 328 ; Mém. Soc. Sci. Hainaut, l. c. 239, t. 19, f. 2. 
It is believed that the fastigiate Poplar originated in Afghanis- 
tan. It is said to grow wild in the forest at Shakkabad, near Cabul, 
at an elevation of seven thousand five hundred feet above the level 
of the sea ; in early times it was commonly cultivated in the coun- 
