STANDLEY — FLORA OF GLACIER PARK. 275 



2. LABEC Adaus. Larch. 



Large or small trees with rough bark; leaves resembling those of pines, but shorter, 

 3oft, and deciduous; cones short-stalked or sessile; seeds winged. 



Branchlets glabrous or nearly so 1. L. occidentalis. 



Branchlets very hairy 2. L. lyallii. 



1. Larix occidentalis Nutt. Western larch. Abundant on the west slope, at 

 low and middle altitudes. B. C. to Oreg. and Mont. — Large tree, often 30 meters 

 high or more; bark bright reddish brown, deeply furrowed at the base of the trunk, 

 but only slightly furrowed above; leaves 3 to 5 cm. long; cones 3 to 4 cm. long. 



Often known as tamarack. Western larch appears to be absent on the east slope, 

 but soon after crossing the pass, along the railroad, it becomes a conspicuous feature 

 of the lansdcape. About Bel ton it is the most abundant tree, and it is common all 

 about Lake McDonald and well up toward Sperry Chalets. It reproduces abund- 

 antly, and in many places the young trees form dense, almost impenetrable 

 thickets. The leaves turn bright yellow in late summer. The wood is valuable for 

 lumber. The species reaches the eastern limit of its range in Glacier Park. 



2. Larix lyallii Pari. Alpine larch. Said to grow in a few places about timber 

 line, but not seen by the writer. Alta. and B. C. to Oreg. and Mont. — A small, often 

 stunted tree, with slightly furrowed bark; leaves 3 to 4 cm. long; cones 4 to 5 cm. 

 long. 



3. PICE A Link. Spruce. 



Large trees with dark rough bark and narrow crowns; leaves pointing in all direc- 

 tions, stiff; cones maturing the first season, the scales thin; seeds with thin wings. 



Twigs glabrous 1. P. canadensis. 



Twigs finely hairy 2. P. engelmanni. 



1. Picea canadensis (Mill.) B. S. P. White spruce. Frequent at middle alti- 

 tudes. Alaska to Lab., N. C, Wis., Wyo., and B. C. — Tree 10 to 20 meters high, 

 with dark scaly bark; leaves bluish green, 1.5 to 2.5 cm. long, curved; cones 3 to 5 

 cm. long, the scales entire or finely toothed. 



2. Picea engelmanni (Parry) Engelm. Engelmann spruce. Common, especially 

 on the east slope, at middle altitudes. B. C. and Yukon to N. Mex. and Ariz. — 

 Large tree, often 25 to 30 meters high, with a narrow pyramidal crown composed of 

 short branches; bark dark purplish brown, with small loose scales; leaves 2 to 3 cm. 

 long, bluish green; cones 3 to 6 cm. long. 



Engelmann spruce is usually associated with fir and Douglas fir, but occasionally 

 it forms almost pure stands. It is a very handsome tree. 



4. ABIES Hill. Fir. 



Large or small trees; leaves lea^'ing rounded scars on the twigs, each leaf with 2 

 longitudinal resin ducts and a solitary fibro-vascular bundle; cones maturing the 

 first year; seeds winged. — The trees of this genus are often known as balsam firs. 



Leaves of the lowest branches arranged in 2 rows (on two sides of the twigs), usually 

 notched at the end; resin ducts of the leaves (as seen in cross section) close to 



the epidermis on the lower side 1. A. grandis. 



Leaves more or less crowded on the upper sides of the twigs, not notched at the end ; 

 resin ducts within the soft tissue of the leaf, remote from the epidennis. 



2. A. lasiocarpa. 

 1. Abies grandis Lindl. Great silver fir. Occasional on the west slope at low 

 altitudes. B. C. to Calif., Wyo., and Mont. — Large tree, often 50 to 75 meters high; 

 twigs finely hairy or glabrous; leaves 2 to 5 cm. long, green above, white beneath;' 

 cones 5 to 10 cm. long. 

 2048—21 4 



