78 



8ILVA OF NORTH AMERICA. 



CONIFERS. 



blue or purple shadings. The buds are acute and about an eighth of an inch in length, with light 

 chestnut-brown scales which in the outer ranks are furnished on the back with conspicuous midribs 

 produced into slender deciduous awl-like tips. The branchlets are thin and flexible, or stout and rigid 

 when the tree has grown slowly in exposed situations at high elevations ; for two or three years they 

 are light reddish brown and covered with short pale dense pubescence which disappears as the thin 

 bark begins to break up into loose scales, and at the end of four or five years they become grayish 

 brown and usually very scaly. The leaves, which stand out from all sides of the branches and are 

 remote on leading shoots and crowded on the short lateral erect branchlets peculiar to this species, are 

 rather abruptly narrowed into nearly straight or slightly twisted petioles, and are raised on persistent 

 bases as long or rather longer than the petioles ; they are rounded and occasionally obscurely grooved, or 

 on young plants sometimes more conspicuously grooved on the upper surface and rounded and slightly 

 ribbed on the lower surface, entire, rather bluntly pointed at the apex, often more or less curved, 

 stomatiferous above and below with about eight rows of stomata on each surface, light bluish green or 

 on some individuals pale blue, from half an inch to an inch in length, about one sixteenth of an inch 

 in width, and irregularly deciduous during their third and fourth years. The staminate flowers are 

 about one sixth of an inch long, with violet-blue anthers furnished with very short basal projections, 

 and are borne on slender pubescent drooping stems from one quarter to nearly one half of an inch in 

 length from buds produced in the axils of the crowded leaves near the extremities of the short lateral 

 branchlets. The pistillate flowers are erect, about a quarter of an inch in length, with delicate lustrous 

 dark purple or yellow-green bracts gradually narrowed above into slender and often slightly reflexed 

 tips. The cones, which are produced in great profusion on all the upper branches, are sessile, 

 cylindrical-oblong, narrowed toward the blunt apex and somewhat toward the base, erect until more 

 than half grown, pendulous or rarely erect at maturity,^ from five eighths of an inch to three inches in 

 length ^ and from three quarters of an inch to an inch in diameter, with thin delicate scales which are 

 as broad as they are long or somewhat narrower, gradually contracted from above the middle to the 

 wedge-shaped base, rounded at the slightly thickened and more or less erose margin, striate and 

 puberulous on the outer surface, and usually bright bluish purple or occasionally pale yellow-green in 

 the exposed parts until the cones ripen, adjacent trees often producing exclusively cones of one and of 

 the other color, especially those growing on the mountains of Washington and Oregon, where the form 

 with yellow cones appears to be more abundant than in other parts of the country; the scales are four 

 or five times as long as their bracts, which are rounded, rather abruptly contracted at the apex Into 

 short points, wedge-shaped and thickened below, with prominent midribs, dark purple above the middle 

 and brown below, or on the form with yellow-green cone-scales brown throughout; at maturity the 

 scales turn dark brown and spread nearly at right angles to the axis of the cone or become much 

 reflexed. The seeds are light brown, one eighth of an inch long, and often marked on the surface next 

 their scale with one or two large' resin vesicles ; their wings are nearly half an inch in length, broadest 

 above the middle, gradually narrowed below and only slightly or not at all obhque at the rounded apex. 

 Tsitga Mertensiana is usually a tree of high altitudes, growing on exposed ridges and slopes at 

 the upper border of the forest, where it is often completely burled in snow during many months of 

 every year, and where its tough and flexible branches and slender leading shoots resist for centuries 



^ Apparently the erect cones are found only on trees which have 

 grown slowly in exposed situations, and their position is evidently 

 due to the thickness of the short lateral branchlets on which they 

 are terminal and which are sometimes so rigid that the weight of 

 the cones does not make them pendent. Trees with erect cones 

 seem to have been first noticed by Mr. M. W. Gorman, who found 

 them, in 1895, small and stunted on slopes and cliffs near the snow- 

 line at altitudes of from three thousand to three thousand five hun- 

 dred feet above the sea on the mountains near Yes Bay, Alaska. 



Similar trees have been seen by Mr. Gorman on the east slope of 

 the Cascade Mountains above Lake Chelan in Washington at clevar- 

 tions of seven thousand feet ; and I have seen a small tree at the 

 sea-level near Sitka which displayed the same peculiarity. 



2 The cones of Tsuga Mertensiana are usually from two to two and 

 a half inches in length. The smallest I have seen were gathered in 

 August, 1895, by Professor S. V. Piper on dry ridges of Mt. Rainier 

 in Washington at an elevation of seven thousand feet above the 

 sea. 



