The Poplars 



The Cottonwood (P. Fremontii, Wats.) grows in western 

 California, from Sacramento south, and eastward to Colorado and 

 Texas. It is a favourite shade tree, and an important source 

 of fuel. Cut back systematically, the trees produce abundant 

 crowns of suckers in a very short time. 



Fremont's cottonwood is distinguishable from the preceding 

 species by the smaller size of its leaves and the pubescence of its 

 buds. Its leaves are sometimes kidney shaped. The bark of old 

 trees is reddish brown. The trees reach loo feet in height. 



The Cottonwood (P. IVisUieni, Sarg.) of the Rio Grande 

 Valley in Texas and New Mexico, is a large, wide-crowned tree, 

 with stout, smooth, orange-coloured twigs and leathery, yellow- 

 green leaves. Without these distinguishing characters it might 

 easily be confused with the two species last described. The tree 

 is not met with outside its natural range. 



Aspen, or Quaking Asp (Populus tremuloides, Michx.) 

 Slender tree, 40 to 80 feet high, with angular, scarred twigs, and 

 large, vigorous roots. Bark rough, dark on base of trunk, be- 

 coming pale greenish brown or nearly white, and marked with 

 broad, dark bands below the limbs. Wood light brown, sap wood 

 white, soft, close grained, light, weak, not durable. Buds waxy, 

 conical, scaly, brown. Leaves alternate, simple, i^ to 2J inches 

 long, ovate or almost round, with straight base and apex acute; 

 margin faintly toothed; thin, shining green above, dull yellow- 

 green beneath; autumn colour yellow; petiole flattened, flexible, 

 slender. Flowers in April, dioecious; catkins pendulous, i^ to 2^ 

 inches long, each flower on notched bract, fringed with hairs; 

 stamens 6 to 12 on disc; ovary conical; stigmas 2-lobed; disc 

 broad, persistent. Fruits, May, borne in drooping aments, 4 

 inches long; capsules oblong-conical, 2-valved, pale green; seeds 

 oblong, covered with brush of long white hairs. Preferred habitat, 

 sandy or gravelly soil, dry or moist. Distribution, Newfoundland 

 to Hudson Bay and Alaska; south to New Jersey, Pennsylvania, 

 Kentucky, Nebraska; also high altitudes throughout the Rocky 

 Mountains and coast ranges. Uses: Most valuable cover for 

 forest land devastated by fire. Comes up from seed scattered 

 broadcast by wind, and acts as nurse to hardwoods and conifers 

 that later succeed them. A pretty shade and ornamental tree, 

 though short lived. 



Aspen is a general term applied to trees of this genus whose 



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