2762 



POPULUS 



POPULUS 



IV. HEAVY or LARGE-LEAVED POPLARS or COTTON- 

 WOODS. Lvs. large and broad, rounded or cordate 

 rather than truncate at base, not lobed, the petiole 

 cylindrical or channelled, not flat, more or less 

 pubescent but becoming mostly glabrous at least 

 above: terminal buds medium to large size, more or 

 less glutinous but scarcely balsamic: trees, mostly of 

 good size. 



15. lasiocdrpa, Oliver (P. Fdrgesii, Franch.). Tree, 

 50-60 ft., with angular stout more or less pubescent 

 young shoots and large viscid buds: Ivs. very large 

 (often 10-14 in. long and 8-9 in. wide), ovate or broad- 

 oblong, acute or short-acuminate, evenly glandular- 

 crenate-serrate, red-veined, deeply cordate at base and 

 biglandular, more or less tomentose beneath but becom- 

 ing glabrous above; petiole nearly cylindrical, red; stip- 

 ules oblong-lanceolate : catkins 4-6 in. long or longer in 

 fruit, the polygamous fls. short-pedicelled; bracts ovate 

 or obovate, finely laciniate; stamens 23 or more in the 

 male fls. and 3-6 in the hermaphrodite fls. : caps, ovoid 

 and densely woolly, to J^in. long. China, common at 

 4,000-6,000 ft. B.M. 8625. R.H. 1911, p. 565. R.B. 

 35, p. 312. G.M. 51:763. P. Wilsonii, Schneid., is a 

 rare tree in W. China, with a pyramidal or columnar head 

 of short spreading branches and strikingly handsome 

 dark bluish green paper-like broad-ovate or roundish 

 or broadly ovate-oblong more or less cordate-based and 

 obtuse Ivs. which are less deeply cordate than those of 

 P. lasiocarpa, and less broadly oblong; it is also distin- 

 guished by its habit, the glabrous and purple rather 

 than tomentose and yellowish branchlets, and' the Ivs. 

 bluish green above and rather whitish gray beneath. 



16. heterophylla, Linn. SWAMP or BLACK COTTON- 

 WOOD. DOWNY POPLAR. A swamp species of irregular 

 branching habit, only rarely planted, reaching 80 ft. 

 and diam. of trunk of 3 ft.: Ivs. densely tomentose 

 when young, but becoming glabrous with age or 

 remaining floccose beneath, 4-7 in. long, broad-ovate in 

 outline, obtuse or somewhat acute at apex, more or less 



3142. 



Populus balsamif era. 

 (XJi) 



truncate or subcordate or rounded at base, serrate, the 

 petiole terete and tomentose or nearly glabrous: stami- 

 nate catkins stout but rather short, stamens 12-20 

 and scales filif orm-lobed ; pistillate catkins slender but 

 rather short, becoming erect or spreading: caps, ovoid- 

 acute, on slender pedicels. Conn, to Ga., La., Ark. and 

 S. Mo.; near the coast in the northern states. S.S. 

 9:489. 



V. BALSAM POPLARS. TACAMAHAC. Lvs. not lobed, 

 varying from broad-ovate to narrower; mature Ivs. 

 whitish but not cottony-tomentose beneath, not clearly 

 translucent-edged; petioles cylindrical or J+-o,ngled, 

 mostly grooved on upper side: terminal buds large 

 to very large, very viscid and balsamic in odor: 

 mostly large trees. 



A. Branchlets terete, without projecting ridges or ribs 

 (except sometimes on strong young shoots). 

 B. Petioles and branchlets mostly glabrous. 



17. balsamifera, Linn. BALSAM POPLAR. TACA- 

 MAHAC. Figs. 3142, 3143. Tall upright tree, with a nar- 

 row top and glabrous twigs: Ivs. thick and firm, erect, 

 whitened beneath, usually smaller than in 



most poplars of this group, glabrous ex- 

 cept that petioles are slightly pubescent, 

 ovate-lanceolate or oval, tapering toward 

 the top and obtuse or narrowly rounded 

 at base, finely and obtusely toothed: cat- 

 kins drooping, slender but rather densely 

 fld., appearing in very early spring; ovary 

 2-carpelled: caps, pedicelled. Mackenzie 

 River to Newfoundland and to Brit. Col., 

 southward in the northern tier of states; 

 not in Asia. S.S. 9:490. Var. Michauxii, 

 Henry (P. Michauxii, Dode. P. cdndi- 

 cans, Amer. Auth. in part, not Ait.), is a 

 form with slightly cordate or rounded- 

 based ovate Ivs. and slightly pubescent on 

 petioles, veins beneath and twigs. G.C. 

 III. 59:230. The native P. balsamifera 

 is sometimes seen about farm buildings 

 and roadsides, where it makes a durable / 

 and interesting tree. The dull whiteness I 

 of the under side of the leaves affords a F 

 pleasant variety and contrast in its foli- | 

 age, and the fragrance of the resinous 

 buds in spring is agreeable to most per- 

 sons. It is a desirable tree for occasional 

 planting, but, like the Lombardy, it gen- 

 erally appears to best advantage when 

 placed amongst other trees. It is a hardier 

 tree than the Lombardy, and does not run 

 quickly to such extravagant heights. In 

 cult., it seems to present a variety of 

 forms or else enters into a number of 

 hybrids. The true P. balsamifera is said 

 to be rare in cult, in Cent. Eu., and only 

 in the male sex. 



In Mont, and Idaho is a balsam poplar 

 with sessile 3-carpelled caps., as in P. tri- 

 chocarpa, although differing in other fr. 

 characters from that species: Ivs. usually 

 broader than in P. balsamifera and often 

 subcprdate, glabrous. This form Rydberg 

 considers to be P. hastata, Dode. 



In the Himalayan region, P. ciliata, Wall., belongs to 

 this group, but it is probably not in cult, in this country: 

 Ivs. ovate or ovate-cordate, acuminate, glabrous except 

 for the gland-ciliate unequal teeth, the base 3-nerved: 

 a large tree, with Ivs. 3-7 in. long. 



18. fortissima, Nels. & Macbr. (P. angustifolia, 

 James, not Weinm. P. balsamifera var. angustifolia, 

 Wats.). Fig. 3144. NARROW-LEAVED COTTONWOOD. 

 Small pyramidal or conical tree (reaching 60 ft. in the 

 wild), with slender twigs and small buds, and soft clear 

 green foliage: bark rough-furrowed: Ivs. small for the 

 genus, lanceolate or ovate-lanceolate, short-stalked, 

 green on both surfaces, finely and evenly serrate: 

 catkins short, densely fld.: ovary somewhat 2-lobed. 

 Interior region from Assiniboia to Neb. and Ariz., and 

 westward; common along mountain streams at middle 

 altitudes in the Rocky Mts. S.S. 9:492. Common 

 street tree in parts of the W. and sometimes planted in 

 the E. for ornament. 



