120 HANDBOOK 148. U.S. DEPARTMENT OF AGRICULTURE 



and leaf scars in V2 arrangement on twigs (each bud or leaf 

 scar 180° around twig from bud or leaf scar next below or 

 above); twigs slender, zigzag, with spreading yellowish (often 

 gland-tipped) hairs; clustered shrubs (sometimes treelike and to 

 25 feet high), often suckering from base, sometimes thicket- 

 forming; mostly w., occasionally e. of Cascades. 



California hazel (Corylus cornuta var. calif or nica). 

 5. Both pollen- and seed-producing flowers in catkins; buds and 

 twigs somewhat resinous; leaf scars with 3 simple (or sometimes 

 compounded) bundle traces; buds and leaf scars in V3 arrange- 

 ment on twigs (each bud or leaf scar 120° around twig from bud 



or leaf scar next below or above) alders and birches. 



6. Seed-producing catkins conelike, persistent, with woody, 

 mostly 5-lobed scales, stalked, in stalked clusters at twig 

 tips; twigs faintly 3-angled, smooth, with pale, dotlike pores 

 (lenticels) but not warty with resin dots; pith triangular in 

 cross section; end buds present, stalked; roots often with (pre- 

 sumably nitrogen-fixing) nodules; buds in clockwise spiral on 



twigs alders (Alnus spp.). 



7. Bud scales overlapping, at least 3; buds stalkless or nearly 

 so (except end buds), sharply taper-pointed at tips, dark 

 purplish; "seeds" (nutlets) tissue-papery -winged; last sea- 

 son's seed-producing catkins long-stalked ; next season's seed- 

 producing catkins hidden in the bud until leaves unfold; 

 seasonal twigs yellow brown, shiny-resinous as are also the 

 pollen-producing catkins; tall, slender shrubs or small trees, 

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

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



Sitka alder (Alnus sinuata). 

 7. Bud scales meeting at edges but not overlapping (valvate), 

 2 or 3; buds distinctly stalked, bluntly pointed or rounded 

 at tips; last season's seed-producing catkins short-stalked to 

 almost stalkless; next season's seed-producing catkins out 

 of the bud by winter but small and undeveloped (white 

 alder usually earlier than red alder). 



8. Trees, commonly to 40 feet high, often much taller; bark 



pale grayish or whitish, smooth except on lower trunks; 



new twigs and pollen-producing catkins shiny-resinous. 



9. Inner bark and sapwood turning orange or bright red 



when freshly cut; pollen-producing catkins brownish to 



red; "seeds" with narrow (often nearly encircling) 



papery wings; seasonal twigs often clear bright red; 



buds dark red; valuable hardwood trees, often in almost 



pure stands on cut- or burned-over areas; mostly w. of 



Cascades, Oreg., Wash. 



red (01 Oregon) alder (Alnus rubra). 

 9. Inner bark and sapwood not as above; pollen-produc- 

 ing catkins pale green to olive brown, becoming red- 

 dish; "seeds" narrowly margined, scarcely winged; 

 twigs greenish at first, becoming dark orange red; buds 

 bright red; both sides of Cascades, common along 

 streams e. Oreg., e. Wash. 



white alder (Alnus rhombifolia) . 



