PINE FAMILY 



63 



Eight species confined to the cooler parts of temperate Noith America and Asia; four are North 

 American. Type species, Tstiga sieboldi Carr. 



Leaves flat, grooved on the upper surface, stomatiferous on the lower surface, rounded at apex. 



1. T. heterophylla. 

 Leaves convex or keeled on the upper surface, stomatiferous on both surfaces, abruptly pointed at apex. 



2. T. mertensiana. 



1. Tsuga heterophylla (Raf.) Sarg. 

 \\ esteni Hemlock. Fig". 134. 



Abies heterophxlla Raf. Atlant. Journ 1: 119. 1832. 

 Abies bridgesii Kell. Proc. Calif. Acad. 2: 8. 1863. 

 Abies albertiana Murr. Proc. Hort. Soc. Edinb. 3: 149. 1863. 

 Tsuga heterophylla Sarg. Sylva N. Am. 12: 7Z. 1898. 



A forest tree often 60-70 m. high, with a narrow 

 pyramidal crown and a trunk 2-3 m. in diameter; 

 branchlets pale yellow-brown, pubescent ; bark on 

 old trees 25-40 mm. thick, deeply divided into broad, 

 flat ridges. Leaves 2-ranked, flat, 6-20 mm. long, 

 rounded at the apex, distinctly grooved, dark green 

 and shining on the upper surface, marked on the 

 lower surface by two broad bands of 7-9 rows of 

 stomata ; staminate flowers yellow ; cones sessile, 

 oblong-oval, 20-25 mm. long ; scales puberulent. 

 longer than broad ; bracts one-fourth the length 

 of the scales, abruptly rounded at the apex and 

 aljruptly contracted at the base ; seeds 3 mm. long, 

 their wings two or three times as long. 



Humid Transition and Canadian Zones; southern Alaska 

 southward along the coast to Mendocino County, California, 

 and eastward through southern British Columbia and Wash- 

 ington to the western slopes of the Bitterroot Mountains, Idaho, and to the western slope of the 

 Cascade Mountains in Oregon. Wood pale yellow-brown, with thin, nearly white sapwood, light, hard, 

 and tough; the strongest' and most durable hemlock, and largely used for building purposes. The bark is 

 the principal source for tanning in the Northwest. Type locality: mouth of the Columbia River, Oregon. 



2. Tsuga mertensiana (Bong.) Sarg. 



Mountain Hemlock. 



Fig. 135. 



Pinus mertensiana Bong. Veg. Sitcha 54. 1832. 



Abies pattoniana Murr. Rep. Bot. Exped. Oreg. 1. pi. 4, 



f. 2. 1853. 

 Abies hookeriana Murr. Edinb. New Phil. Journ IL 1: 



289. pi. 9, f. 11. 17. 1855. 

 Abies williamsonii Newb. Pacif. R. Rep. 6: 53. pi. 7, f. 



19. 1857. 

 Tsuga roezlii Carr. Rev. Hort. 1870: 217. /. 40. 1870. 

 Tsuga mertensiana Sarg. Sylva N. Am. 12: 77. 1898. 

 Hesperopeucc mertensiana Rydb. Bull. Torrey Club 39: 



100. 1912. 



An alpine forest tree 25-50 m. high, with an 

 open pyramidal crown and a trunk 9-12 dm. in 

 diameter ; branches slender, curved ana pendent, 

 the branchlets drooping with their tips often 

 curved upward ; bark on old trees 25-35 mm. 

 thick, deeply divided into rounded ridges, 

 covered with closely appressed red-brown scales. 

 Leaves spreading from all sides of the branch- 

 lets, more or less curved, 15-20 mm. long, blunt- 

 pointed, narrowed toward the base, light blue- 

 green and stomatiferous on both sides, convex 

 above, rounded below ; staminate flowers bluish ; cones sessile, oblong-cylindric, narrowed 

 toward both ends, 25-75 mm. long; scales very thin, usually as broad as long, gradually 

 narrowed from near the middle toward the wedge-shaped base ; bracts one-fourth the length 

 of th« scales, sharp-pointed at the apex and wedge-shaped at the base ; seeds 3 mm. long, with 

 wings about four times as long. 



An alpine species growing on the upper edge of the forests, Hudsonian Zone; southern Alaska south- 

 ward through the Olympic and Cascade Mountains and the Sierra Nevada to Kings River, California, and 

 eastward to the Selkirk Mountains, northern Idaho, and Montana. Type locality: Sitka. 



5. PSEUDOTSUGA Carr. Trait. Conif. ed. 2, 256. 1867. 



Pyramidal trees with long whorled branches, usually drooping branchlets and rough 

 furrowed bark. Leaves flat, appearing 2-ranked by a twist at the base, narrowed into a 

 short petiole, grooved on the upper surface and dark green, paler beneath, with several 

 rows of stomata on either side of the midrib, with 2 lateral resin ducts seen in a cross section 

 of a leaf, falling away after from 6-8 years, leaving a rounded sessile leaf scar. Flowers 

 monoecious, appearing in early spring from buds formed the previous year, surrounded 

 by large membranous scales, the staminate axillary, appearing on the lower side of the 

 branchlets, oblong-cylindrical, nearly or quite sessile, consisting of many short-stalked, 



