22 HANDBOOK 14S, U.S. DEPARTMENT OF AGRICULTURE 



5. Seed-producing catkins long-stalked, on new leafy shoots, 

 appearing with the leaves; "seeds" tissue-papery-winged, 

 leaves shiny on under surface, sticky when young, yellowish 

 or bright green on upper surface ; margins doubly and finely 

 glandular-saw-toothed; buds stalkless or nearly so; bud 

 scales 3 or more, overlapping; tall, slender shrubs or small 

 trees, often thicket-forming; along cool mountain streams, 

 Cascades, Wallowa and Blue Mts., e. Oreg., e. Wash. 



Sitka alder (Alnus sinuata). 

 5. Seed-producing catkins short-stalked, on last year's twigs, 

 in leafless clusters, appearing before the leaves; buds mostly 

 stalked; bud scales 2 (or 3), meeting at edges but not over- 

 lapping (valvate). 



6. Leaves shiny dark green above, paler and often sticky 

 underneath; margins finely (sometimes doubly) glandular- 

 toothed, usually not lobed; leafstalks flattened on upper 

 side, slender, hairy, glandular; "seeds" narrowly margined; 

 inner bark and sapwood not turning red when peeled; 

 large trees, commonly to 40 feet high;. both sides of Cas- 

 cades, along streams, e. Oreg., e. Wash. 



white alder (Alnus rhombifolia) . 

 6. Leaves dull green on both sides, not sticky; margins usu- 

 ally lobed; leafstalks round in cross section. 

 7. Leaf margins blunt-toothed, thickened, rolled under; 

 "seeds" with narrow, nearly encircling papery wings; 

 inner bark, sapwood turning bright red or orange when 

 peeled; large, valuable hardwood trees, often in almost 

 pure stands on burns or logged-over areas w., rare e. of 

 Cascades; type locality, probably w. Oreg. 



red alder (Alnus rubra) . 

 7. Leaf margins doubly saw-toothed, not thickened or 

 rolled under; "seeds" narrowly margined; seed-produc- 

 ing catkins often diseased, with enlarged curly bracts; 

 tall shrubs or small trees, often thicket-forming; com- 

 monest alder in e. Oreg., e. Wash. 



thinleaf alder (Alnus tenuifolia). 

 4. Twigs round, sparsely resin-dotted or densely resin- warty 

 when young, becoming smooth and dotted with pale pores 

 (lenticels) ; leaves in a 1/3 counterclockwise arrangement on the 

 twigs; pith compressed, small; seed-producing catkins tassel- 

 like, not persistent except for their erect or recurved central 

 stalks from which the 3-lobed papery scales fall either with or 

 after shedding of the tissue-papery-winged "seeds"; buds with 

 3 or more overlapping bud scales ; shrubs or trees of moist sites, 



sometimes thicket-forming birches (Betula spp.) . 



8. Bark at base of old trunks shredding or separating into 

 layers; leaves dull green on both sides, sharp- or taper- 

 pointed at tips; second-year twigs usually smooth except for 

 whitish dotlike pores (lenticels) ; trees. 



paper birches (varieties of Betula papyrif era). 

 9. Leaves square-cut or broadly (sometimes unevenly) 

 wedge-shaped at base, thin; margins finely, doubly saw- 

 toothed, slightly lobed; new twigs sparsely resin-dotted, 

 with straggly white hairs, becoming shiny orange-brown 



