33. sweetgale, Myrica gale L. (SS-MS, I-C). Southeastern, 

 south-central, and interior Alaska. Throughout lowlands of south- 

 east except the outer islands; northwest along the coast to Prince 

 William Sound; north only in lowlands along rivers to the 

 Tanana and Yukon Rivers and to Wiseman in southern foothills 

 of Brooks Range; west to isolated occurrences on Norton Sound 

 and at McGrath on the Kuskokwim River; south to isolated 

 localities at mouth of Kuskokwim River, head of Bristol Bay, 

 and Alaska Peninsula; and east to Kodiak Island and Kenai 

 Peninsula. From Alaska east across Canada to southern end of 

 Hudson Bay, Labrador, and Newfoundland, south in mountains 

 to North Carolina and Tennessee and to northwest Oregon. 

 Also in northern Europe and eastern Asia and Japan. 



34. dwarf arctic birch, Betula nana L. (SS-MS, I-c). Very 

 widespread nearly throughout interior Alaska, north almost to 

 Arctic Ocean, west to Bering Sea and western end of Alaska 

 Peninsula. South of Alaska Range to Kodiak Island, Kenai 

 Peninsula, and Copper River drainage. Also local in northern 

 end of southeast Alaska at Yakutat and head of Lynn Canal at 

 Haines and Skagway. Alaska, across northern Canada to Labra- 

 dor and Greenland. Not in contiguous United States. Also across 

 northern Eurasia. 



35. resin birch, Betula glandulosa Michx. (SS-MS, I-c). 

 Widely distributed in interior Alaska from Firth River, northern 

 Brooks Range, and Noatak and Kobuk Rivers southward to 

 Tanana, Farewell, northern Kenai Peninsula, and Copper River 

 drainage. Also local near Haines at northern end of southeast 

 Alaska. Alaska, across northern Canada to Labrador and Green- 

 land, south in Northeastern United States to Maine, New York, 

 Michigan, and Minnesota, and in western mountains to Colorado 

 and California. 



36. * paper birch, Betula papyrifera Marsh. (ST-LT, 

 I-C). Through interior Alaska corresponding to the range of 

 the spruce-hardwood forest but not quite so far north and west. 

 North to south slopes of Brooks Range west to Kobuk River, also 

 local on Noatak River, and to coast on south side of Seward Penin- 

 sula, south to Unalakleet, Marshall on Yukon River, Dillingham, 

 Alaska Peninsula to Naknek Lake, and Afognak and Kodiak 

 Islands. South of Alaska Range in Susitna Valley, Kenai Penin- 

 sula, and Copper River Valley. Also local in southeast Alaska 

 at northeast end in vicinity of Lynn Canal from Skagway and 

 Haines to Juneau and Taku River, also Tidal Inlet in Glacier 

 Bay National Monument, and at southeast end at Hyder on 

 Portland Canal. From northwest Alaska east across Canada to 

 Labrador and Newfoundland, south in northeastern States to 

 Pennsylvania and Iowa and in western States to Montana and 

 northeastern Oregon (locally south to Nebraska and in mountains 

 to North Carolina, South Dakota (Black Hills), and Colorado). 



Paper birch is one of the most widespread tree species in 

 northern North America and is composed of 6 or fewer inter- 

 grading geographical varieties. The 3 varieties in Alaska listed 

 below are mapped together here but are further distinguished by 

 key, description, drawing, and small map in "Alaska Trees and 

 Shrubs." The last 2 intergrade or hybridize where their ranges 

 meet and overlap. 



36a. western paper birch, Betula papyrifera var. commutata 

 (Reg.) Fern. Southeast Alaska and eastward. 



36b. Alaska paper birch, Betula papyrifera var. humilis (Reg.) 

 Fern. & Raup. Through most of interior Alaska and eastward. 



36c. Kenai birch, Betula papyrifera var. kenaica (W. H. Evans) 

 Henry. Southern part of interior Alaska from Cook Inlet, Kenai 

 Peninsula area, and west to Kodiak Island and base of Alaska 

 Peninsula. Known only from Alaska. 



37. American green alder, Alnus crispa (Ait.) Pursh 

 (MS-ST, I). Widely distributed in interior Alaska north to Col- 

 ville River, north slopes of Brooks Range, Firth, Porcupine, Yukon, 

 Koyukuk, Kobuk, and Noatak Rivers, and west to Bering Sea; 

 south to Bethel and Alaska Range and southward in Susitna and 

 Copper River Valleys, locally beyond. Alaska and Yukon Terri- 

 tory across Canada to Labrador, Newfoundland, and Greenland, 

 south to New York, North Carolina (high mountains), Michigan, 

 and Oregon. Also across northern Asia. 



38. Sitka alder, Alnus sinuata (Reg.) Rydb. (LS-ST, 

 I-C). Along Pacific coast of southeastern, southern, and south- 

 western Alaska. Through southeast Alaska from Portland Canal 

 northeast to head of Lynn Canal at Skagway and to Yakutat; 

 west along coast to Prince William Sound, Cook Inlet, Kenai 

 Peninsula, Afognak and Kodiak Islands, and through Alaska 

 Peninsula to Unimak Island in eastern Aleutians. Also northward 

 in Susitna and Copper River Valleys and locally beyond. From i 

 southwestern Alaska along Pacific coast east to Yukon Territory, 

 southeast to southwestern Alberta, western Montana, and northern , 

 California. Also in northeastern Asia. Intergrades with the pre- 

 ceding, American green alder {Alnus crispa (Ait.) Pursh), espe- 

 cially northward in interior, and often treated as a variety or 

 subspecies of that species. 



39. red alder, Alnus rubra Bong. (ST-MT, C). Through 

 southeast Alaska from Portland Canal northwest to Skagway at 

 head of Lynn Canal and to Yakutat. Pacific coast region from I 

 southeast Alaska southeast to southern California; also locally 

 east to northern Idaho. i 



40. thinleaf alder, Alnus tenuifolia Nutt. (LS-ST, I-C). 

 Interior Alaska from Yukon River Valley west to mouth of Yukon 

 River, south to Bethel on Kuskokwim River, and base of Alaska 

 Peninsula at Katmai, and east to Kenai Peninsula and Copper 

 River Valley. Also north end of southeast Alaska from Juneau 

 to Haines. Alaska and Yukon Territory southeast to southwestern 

 Saskatchewan and south in mountains to New Mexico and Cali- 

 fornia. 



41. hemlock dwarf-mistletoe, Arceuthobium tsugense 

 (Rosend. ) G. N. Jones (Parasite, C). Generally distributed 

 through coastal forests of southeast Alaska from south end of 

 Portland Canal northwest to Haines near head of Lynn Canal 

 and to Chichagof and Yakobi Islands. Southeast Alaska south 

 in coastal forests to Oregon and to Sierra Nevada in central 

 California. 



42. stink currant, Ribes bracteosum Dougl. (MS-LS, C). 



Pacific coast from southeastern tip of Alaska northwest to Prince 

 William Sound. From Alaska south along coast to northwestern 

 California. 



43. skunk currant, Ribes glandulosum Grauer (SS-MS, 



I). Of very erratic occurrence in south-central, interior, and 

 southwestern Alaska. Scattered locations from near Valdez in 

 Prince William Sound northward to Tanana River at Fairbanks 

 and Manley Hot Springs and in Mt. McKinley National Park; 

 several locations in Susitna Valley; southwestward to isolated 

 localities on Stony River and in Dillingham area; and east to 

 a location at Homer on Kenai Peninsula. 



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