74 



SILVA OF NORTH AMERICA. 



CONIFEEiE. 



r 



the acute scales. The cones are oblong-oval, acute, sessile, from three quarters of an inch to an inch 

 in length, and slightly puberulous on the outer surface of the scales, which are longer than they are 

 broad, often abruptly narrowed near the middle, thin, striate on the outer surface, green more or less 

 tino-ed with purple toward the margins until fully grown, and light reddish brown at maturity ; their 

 bracts are dark purple, puberulous, and rounded and abruptly contracted at the apex into short points. 

 The seeds are about an eighth of an inch in length, with only occasional oil vesicles, and are from 

 one half to one third as long as their narrow wings. 



Tsuga heterophylla is common in southeastern Alaska/ where it forms with the Tideland Spruce 

 the largest part of the great coast forest which extends from the sea-level up to elevations of about two 

 thousand feet, sometimes one species and sometimes the other predominating. In British Columbia it 

 is very abundant on the coast ; it extends up the valley of the Fraser and other rivers in the southern 

 part of the territory to the Hmit of the region of abundant rains, and, reappearing on the Selkirk and 

 Gold Rangesj spreads eastward along the Kicking Horse to the western slopes of the continental divide.^ 

 It is one of the commonest and largest trees in the coniferous forest which extends from the coast 

 of Washington and Oregon to the western slopes of the Cascade Mountains,^ and in the Redwood 

 forests of the California coast as far south as Cape Mendocino, finding its southern home in Marin 

 County, In the interior Tsuga heterophylla ranges eastward along the mountains of northern Wash- 

 ington to the western slopes of the Rocky Mountains of northern Montana and to the Coeur d'Alene 

 and Bitter Root Mountains of Idaho.^ Although it is most abundant and of largest size In the moist 

 valleys and on low slopes near the coast, Tsuga heterophylla in the interior, where it sometimes ascends 

 to elevations of six thousand feet above the sea, attains a large size when it is abundantly supplied with 

 moisture, and in northern Montana and Idaho and in southern British Columbia often forms a consid- 

 erable part of the forests, in which it is associated with the White Fir, the Douglas Spruce, the Mountain 

 Pine, the western Larch, and the Engelman Spruce.^ 



The wood of Tsuga heterophylla is light, hard, and tough ; it is pale brown tinged with yellow, 

 with thin nearly white sapwood, and contains thin inconspicuous bands of small summer cells and 



1 Kothrock, Smithsonian Rep. 1804,433 (FL Alaska). — Mee\i2m, 

 Proc. Phil. Acad. 1884, 93. -- F. Kurtz, Bot Jahrh. xis. 425 {Fl. 

 Chilcatgehletes). ■ — Gorman, Pitionia, iii. 68. 



The most western point on the Alaska coast where Tsuga hetero- 

 phylla has been observed is on Hinchiubrook Island at the mouth 

 of Prince William Sound in latitude 60° 13' north, where it was 

 seen by Dr. J. M. Macoun on June 18, 1892. The Spruce forest, 

 however, extends along the shores of Prince William Sound and cov- 

 ers the eastern extremity of Kadiak Island, where the Pacific forests 

 end, and it is not impossible that the Hemlock may still be found 

 farther to the westward, although on the shores of Yakutat Bay, in 

 latitude 60°, it is said to be less abundant and of smaller size than 

 the Spruce. (See Funston, Contrih. U. S. Nat. Herh. iii. 328.) It is 

 common but of small size on the lower seaward slopes of the moun- 

 tains at the head of the Lynn Canal, a hundred miles north of 

 Sitka and also near the sixtieth degree of latitude. On Baranoffi 

 Island it grows to a very large size a few feet above the sea-level ; 

 and between Cross Sound and Cape Mendocino, a distance of 

 nearly fifteen hundred miles, it is one of the commonest trees in 

 the humid coast region, in Alaska usually ascending above the 

 Spruce, its constant companion at the north, and southward min- 

 gling also with the Douglas Spruce, the White Fir, and the Arbor 



Vitse, and in California with the Redwood. 



2 G, M. Dawson, Can. Nat. n. ser. ix. 324. — Macoun, Cat. Can. 

 PI 471. 



On the western slope of the Selkirk Mountains of British Co- 

 lumbia the Hemlock is abundant and of large size up to elevations 



r 



of about five thousand feet above the sea-level, often forming a 



large part of the forest growth, being mingled with the Engelmann 

 Spruce, the Patton Spruce, and the Mountain Fir. 



^ The most southern point on the western slope of the Cascade 

 Mountains at which Tsuga heterophylla has been noticed is at the 

 northern base of Huckleberry Mountain in the valley of Union 

 Creek and about twelve miles southwest of Crater Lake (Coville 



in litt.). 



* Leiberg, Contrih. U. S. Nat. Herb. v. 54. 



^ Without regular and abundant supplies of watex Tsuga hetero- 

 phylla remains small and stunted, and in the search for moisture 

 trees which have sprung up on dry slopes will send their roots for 

 great distances near the surface of the ground to springs at lower 

 levels. 



In the coast region, where this tree delights in the humidity 

 which every breeze brings in from the ocean, the forest floor is so 

 deeply covered with mosses and with many strong growing shrubs 

 that the delicate seeds of the Hemlock often find their only oppor- 

 tunity to germinate on the trunks of fallen trees, which, in conse- 

 quence, are frequently covered with miniature Plemlock forests. 

 Some of these seedlings, more vigorous than their companions, 

 survive the hardships of overcrowding, and, sending their roots 

 into the jrround around the trunks which had been their seed-beds, 

 grow into great trees. Like those of some tropical Fig-trees, the 

 seeds of the Hemlock sometimes germinate in the humid coast 

 forests high in tbe air on the broken stems of trees, and, sending 

 stout and vigorous roots down to the ground, continue to live long 

 after their hosts have disappeared. 



