PINACEAE. 19 



A common lowland tree, especially in moist soil, ranging from Alaska to 

 northern California. Found originally by Menzies at Nootka Sound. The 

 northernmost station known is the head of Lynn Canal, Alaska. 



27. LIBOCEDRUS. 



Resinous trees with scaly bark and spreading branches; leaves 

 scale-like, dimorphic, opposite, persistent; flowers naked, monoe- 

 cious or dioecious, terminal, solitary; stamens numerous; anther- 

 cells usually 4; scales of pistillate cone 4 or 6, acuminate; ovules 

 2; fruit maturing in one season. 



Libocedrus decurrens Torr. Incense Cedar. Tree, 30-50 m. high; bark 

 fibrous, loose; leaves opposite, adnate, the acute tips spreading; cones 20-30 

 mm. long. 



In the mountains, Clackamas County, Oregon, and southward to Lower 

 California. 



28. PINUS. Pine. 



Evergreen trees with two kinds of leaves; the primary ones 

 scale-like with deciduous tips; the secondary ones forming the 

 ordinary foliage, needle-like, arising from the axils of the former 

 in clusters of 2-5; ovule-bearing aments solitary or clustered, 

 each composed of numerous minute bracts, each with an ovule- 

 bearing scale in its axil; ament, upon maturing, becoming a cone, 

 the scales elongating and becoming woody; seeds two on the 

 base of each scale. 



Leaves 5 in each fascicle; scales of the cones unarmed. 



Cones ovoid to subglobose, 4-8 cm. long; wing of seed 



shorter than the body. P. alhicaulis. 



Cones cylindric-oblong; wing of seed longer than body. 



Seeds 5-7 mm. long; cones usually 10-20 cm. long. P. monticola. 



Seeds 9-12 mm. long; cones usually 20-30 cm. long. P. lambertiana. 

 Leaves 2 or 3 in each fascicle; scales of the cones thickened, 

 each armed with a sharp spine on the back. 

 Leaves in twos; cones small, 4-5 cm. long. P. conlorta. 



Leaves in threes; cones larger. 



Cones persistent for several years, formed well below 



the apex of the shoot; small tree. P. aUeuuata. 



Cones falling after the second year, formed subter- 



minally on the young shoot; large tree. P. ponderosa. 



Pinus albicaulis Engelm. White-hark Pine. Scraggly tree, 20-30 m. 

 high; bark nearly white; leaves 4-7 cm. long; cones oval, 5-7 cm. long, the 

 scales much thickened; seeds large, edible. 



British Columbia to Montana and California. In our limits only in the 

 Cascade Mountains at 1500-2100 m. elevation. 



Pinus monticola Dougl. Western White Pine. Tree 50-100 m. high, 1-2 

 m. in diameter; bark gray, rather smooth, longitudinally cracked; leaves pale 

 green, in fascicles of five, 4-7 cm. long; cones narrowly cylindrical, 15-30 cm, 

 long, about 4 cm. thick. 



This tree usually occurs in colonies along with the red fir. It ranges from 

 the sea level to 1700 m. altitude and extends from British Columbia to Montana 

 and California. It does not extend farther north than Vancouver Island. 



