i68 



The Poplars 



leaves in March, April, or May. The staminate catkins are about 5 cm. long, 

 the pistillate longer, at least in fruit. 



The Abele tree is of rapid growth. The wood is light, soft, and weak, difficult 

 to split and to ignite, and is used in Europe for rollers, packing-cases, and floor- 

 ing; in ancient times it was used for shields, for which it was wtU adapted, 

 yielding under a blow without splitting. 



2. SWAMP POPLAR Populus heterophylla Linnjeus 



The Swamp poplar, or Downy poplar, inhabits wet, rich soil, and occurs from 

 Connecticut to New Jersey, south to Georgia, westward to Missouri, Arkansas, 

 and Louisiana. In the southwestern parts of its range it is sometimes about 30 

 meters high and has a trunk a meter in diameter. 



The thick bark is brown and fissured, or broken into loose, long, and narrow 

 plates. The stout young twigs are velvety, becoming gray to reddish brown, and 



somewhat shining. The slightly resinous leaf- 

 buds are ovoid, pointed, and about 6 mm. long. 

 The long-stalked leaves are 12 to 15 cm. long, 

 or those of young shoots much larger; they are 

 broadly ovate, firm in texture, very velvety when 

 young, blunt or bluntish, finely toothed, rounded 

 to heart-shaped at the base, when mature dark 

 green, dull and smooth, or a little cottony on 

 the upper side, smooth or nearly so beneath; 

 those of young shoots are sometimes persistently 

 velvety; the narrow stipules are 3 cm. long or 

 less. The tree flowers, according to latitude, 

 in March, April, or May, before the leaves un- 

 fold. The staminate catkins are stout, stalked, 

 densely many-flowered, 2.5 cm. thick or less, 

 and 7 to 10 cm. long, their scales cut into nu- 

 merous filiform lobes, the stamens 20 or fewer. The smooth pistillate catkins are 

 several-flowered racemes, 5 cm. long or more, elongating in fruit to several times 

 that length, the flower-stalks also elongating, often becoming 1.5 cm. long; the 

 stigma- lobes are short and much dilated. The capsule is ovoid, pointed, 8 to 12 

 mm. long. 



The tree is also known as Black poplar, Black cottonwood, and Swamp cotton- 

 wood. Its wood is soft and brown, with a specific gravity of about 0.41, and is 

 locally used for construction, though not of much value. 



Fig. 123. Swamp Poplar. 



3. BALSAM COTTONWOOD Populus trichocarpa Torrey and Gray 



The tallest of all poplars, this tree occurs mainly along streams from southern 

 Alaska to southern California, perhaps extending eastward to Montana, attaining 



