262 



The Alders 



3. OREGON ALDER 



Alnus rubra Bongard 

 Alnus oregona Nuttall 



The Oregon alder is a tall forest tree, attaining a maximum height of about 

 28 meters and a trunk diameter of a meter or more. It inhabits the vicinity of 

 the Pacific coast, extending from CaHfornia to Alaska, preferring moist soil. 



The bark is nearly smooth, light gray or whitish. The young twigs are finely 

 velvety and green, becoming smooth, reddish, and gray. The somewhat hairy 

 buds are 6 to 8 mm. long. The leaves are ovate or oval, pointed or bluntish, 



rather firm in texture, prominently straight- 

 veined, usually from 6 to 12 cm. long, but 

 sometimes larger, coarsely toothed with the 

 teeth again dentate ; when fully grown they 

 are smooth and dark green on the upper 

 surface, brown-hairy, particularly along the 

 orange-colored veins beneath, but some- 

 times only slightly so; the leaf-stalks are 

 stout, orange yellow, i to 2 cm. long; the 

 small ovate pointed stipules fall early in the 

 season. The catkins of staminate flowers 

 are i to 1.5 dm. long at the time of flower- 

 ing in early spring, before the leaves unfold ; 

 the calyx of the staminate flower is 4-lobed 

 and there are 4 stamens with anthers about 

 as long as the filaments. The ripe pistillate 

 catkins are 2.5 cm. long or less, their scales 

 thickened at the apex. The nut is 2.5 mm. long, bordered by a thin wing of only 

 about one third its width. 



The wood is weak, brittle, Hght reddish brown, and takes a good polish; the 

 specific gravity is about 0.48; it is used in large amounts on the Pacific coast for 

 furniture, and in Alaska is made into canoes by the Indians. 



Fig. 220. Oregon Alder. 



4. THIN-LEAVED ALDER Alnus tenuifolia Nuttall 



While usually a shrub, this species sometimes becomes a tree 8 to 10 meters 

 high, with a trunk about 2 dm. thick. It occurs along streams and lakes from the 

 Yukon Territory' and British Columbia south through the Rocky mountain region 

 to Colorado and New Mexico, and along the Sierra Nevadas to Lower CaHfornia. 



Its thin, reddish brown bark is finely scaly when old. The twigs are at first 

 finely brown-velvety, but soon become smooth and light brown. The buds are 

 red, minutely hair\', and 6 to 8 mm. long. The leaves are ovate or oval, often 

 broadly so, rather thin, pointed or bluntish, coarsely doubly toothed or shallowly 



