218. POPULUS TKICHOCARPA BLACK CoTTCXNWOOD. 4:1 



PHYSICAL PROPERTIES. Wood light, soft, brittle, with many fine 

 and occasionally large medullary rays, close grain, easily worked and 

 susceptible of a beautiful polish. It is of a light brown color with 

 abundant buff-white sap-wood which quickly assumes a brownish tint 

 upon exposure to the air. Specific Gravity, 0.4:813; Percentage of 

 , 0.42; Relative Approximate Fuel Fa/w?, 0.4793; Coefficient of 

 , 106046; Modulus of lt">t"re, 811; Resistance to Lonqi- 

 tudinal 7V' : .v.v///v, 415; Resistance to Indentation, 111; Weight of a 

 Foot in Pounds, 29.99. 



. Used in Washington and Oregon in the manufacture of 

 furniture, for wooden ware, etc., and in Alaska is a favorite wood 

 with the Indians in making their dug-out canoes. 



ORDER SALIC ACE2E: WILLOW FAMILY. 



Leaves alternate, simple, undivided and furnished with stipules, which are 

 either scale-like and deciduous, or leaf -like and persistent. Flowers dioecious, 

 both kinds in catkins, one under each bract or scale of the catkin and destitute 

 of both calyx and corolla, or the former represented by a gland-like cup; ovary 

 1 to 2 celled; styles wanting, or 2 and short; stigmas often 2-lobed. Fruit a 1 or 

 2-celled, 2-valved pod, with numerous seeds springing from two parietal or basal 

 placentae and furnished with long, silky down; seeds ascending, anatropous, 

 with albumen; cotyledons flat. 



Trees or shrubs of rapid growth, light wood and bitter bark. 



GEXUS POPULUS, TOURXEFORT. 



Leaves broad, more or less heart-shaped or ovate, and with long and often ver- 

 tically compressed petioles. Flowers appearing before the leaves in long, droop- 

 ing, lateral, cylindrical catkins, the scales of which are furnished with a fringed 

 margin; calyx represented by an oblique, cup-shaped disk with entire margin; 

 stamens. 8-30 or more, with distinct filaments: pistil with very short, bifid style, 

 and large 2-lobed stigma. Fruit as described for the order. 



Genus represented mostly by rather large trees, and the name is a Latin word, 

 meaning people, applicable either from the fact that these trees are often set 

 along public walks, or in allusion to the tremulous motion of the leaves, which 

 are in constant agitation like a crowd of people. 



218. POPULUS TRICHOCARPA, T. & G. 

 BLACK COTTOXWOOD. 



Gei., Schwarze Pappel; Fr., Peuplier noir; SP., Alamo negro. 



SPECIFIC CHARACTERS: Lea ces broad-ovate to oblong-lanceolate, 2-4 in. long 

 (exclusive of petioles), rounded or slightly heart-shaped at base, acuminate, finely 

 crenate- serrate with small incurved gland-tipped teeth, pale pubescent when 

 young, but at maturity lustrous dark green above, pale or rusty beneath and con- 

 spicuously reticulate veined, glabrous excepting: along the veins above: petioles 

 1-2 in. long slender, terete puberulous: leaf buds long-pointed and shining, fra- 

 grant- viscid; branchlets pubescent at first and angled, especially the more vigor- 

 pus ones, but finally terete and lustrous with elevated lunate leaf scars. Flowers 

 in early spring in pedunculate pendulous aments; the staminate li-2 in. long, 

 denselv flowered and with glabrous rhachis; the pistillate araents~2-3 in. long 

 (becoming 6) and with pubescent rhachis: scales dilated, deeply fimbriated, nearly 



