656 ORDER 123. SAURURACE^E. 



long and of equal or greater width), dark green, petioles 2 to 3' long and laterally 

 compressed, so that they can scarcely remain at rest in any position, and aro 

 thrown into excessive agitation by the slightest breeze. The trembling of tho 

 "aspen loaf" is proverbial. Amenta plumed with silken hairs, about 2' long, 

 pendulous. Apr. 



4 P. grandidentata MX. LARGE POPLAR. Los. roundish-ovate, acute, with 

 large, unequal, sinuate teeth, smooth, villous when young; bracts fan-shaped, 5-cleft 

 and silky-fringed. Woods and groves. Can. and Nor. U. S. not uncommon. 

 St. 40f high, with a diam. of If, straight, covered with, a smooth, greenish bark. 

 Branches distant, coarse and crooked, clothed with leaves only at their ex- 

 tremities, with terete twigs. Lvs. 3 to 5' long and nearly as wide, clothed 

 with thick white down in spring, but becoming perfectly smooth. Aments 3 to 

 4' long, all the parts hairy, the sterilo longer thau the fertile. Stain, about 12, 

 as in the preceding species. May. 



5 P. heterophylla L. COTTON TREE. Branches terete; Ivs. roundish-ovate, 

 obtuse, uncinately serrate, cordate at base, the small auriculate lobes over-closed, 

 white-tomentous when young, at length nearly smooth ; ovaries with a long pedicel 

 and conspicuous style. Swamps, N. Eng. (rare) to 111. and La. A tree 40 to 60f 

 high, trunk 1 to 2f diam. Lvs. 3 to 6' long, with small teeth, blunt or never 

 acuminate at apex, and the base lobes often so overlapping as to conceal tho 

 insertion of the petiole. Apr., May. 



5 P. balsamifera L. BALSAM POPLAR. TACAMEIIAC. Branches terete ; Ivs. ovate, 

 acuminate, with close-pressed serratures, white and reticulate-veiny beneath, 

 glabrous both sides; bracts of the ament dilated, laciniate-fringed, slightly hairy ; 

 stam. 40 to 50. Swamps and river banks, Me. to Penn., N. Y., Can. and the N. 

 W. coast. A largo tree, 40 to 80f high, trunk 1 to 2f diam. Lvs. 2 to 4' long. 

 Sterile amenta 2 to 3' long, fertile at length 4 to 6'. Stain, purple. Buds in spring 

 covered with an aromatic resin which may be separated in boiling water. 



7 P. candicans Ait. BALM or GILEAD. (Fig. 268, 269). Branches terete, Ivs. 

 ovate, cordate, acuminate, closely and unequally serrate, whitish and reticulate- 

 veined beneath, petiole hirsute ; bracts of the ament oval, laciniate-fringed ; stam. 

 about 20. A fine tree of strong and peculiar fragrance, often cultivated, rarely 

 growing wild, Can. and the Northern U. S. Height 30 to 50f, with a pyramidal 

 head of dense ample foliage. Lvs. 4 to G' long, at length smooth and dark green 

 above. Sterile aments 2 to 3' long, fertile 4 to 6. Buds filled throughout with 

 fragrant resin. 



P. nigra L. /?. BETULIFOLIA Torr. BLACK POPLAR. Young branches pubes- 

 cent; Ivs. deltoid-rhombic, conspicuously acuminate, finely crenate-serrate, smooth 

 both sides; aments without hairs. Trees 30 to 40f high, planted at Hoboken, 

 N. J. and perhaps in Penn. f Eur. (P. betulifolia Ph. P. Iludsonica MX.) 



9 P. dilatata Ait. LOMBARDY POPLAR. Lvs. smooth, acuminate, deltoid, 

 serrate, the breadth equaling or exceeding the length ; trunk lobed and sulcate. 

 Early brought to this country, and has been planted about many a dwelling and 

 in village streets. Its rapid growth is the only commendable quality it possesses, 

 while tho huge worms by which it is often infested render it a nuisance. 

 f Italy. 



10 P. alba L. ABELE. SILVER-LEAP POPLAR. Lvs. cordate, broad-ovate, 

 lobed and toothed, acuminate, dark green and smooth above, very white-downy 

 beneath ; fertile amenta ovate ; stig. 4. A highly ornamental, cultivated tree. 

 Nothing can be more striking than tho contrast between the upper and lower 

 surface of tho leaves, f Eur. 



ORDER CXXIII. SAURURACE^E. SAURURADS. 



Serbs with jointed stems, alternate, entire leaves furnished with stipules. Flow- 

 ers in spikes, perfect, naked, having neither corolla nor calyx. Stamens definite. 

 Ovaries 3 to 5, more or less tmited. Sseds ascending. Embryo enclosed in a eac 

 (amnios), outside of hard, mealy albumen. Fig. 264. 



