. The Canadian field-naturalist. Natural history. 1970 ViERECK AND FOOTE: POPULUS IN ALASKA 171. Figure 1. Distribution of Populus balsamifera and Popidus trichocarpa in Alaslca and adjacent Canada (from Powells 1965, Hulten 1968, Taylor and Little 1950, and Wiggins and Thomas 1962). tree at each site. If no mature capsules were present on the tree, they were collected from the ground directly beneath. Hybrid index of herb- arium specimens was determined from whatever material was available — usually one to three aments. Collections were made during the summer of 1967 and 1968, whenever other
. The Canadian field-naturalist. Natural history. 1970 ViERECK AND FOOTE: POPULUS IN ALASKA 171. Figure 1. Distribution of Populus balsamifera and Popidus trichocarpa in Alaslca and adjacent Canada (from Powells 1965, Hulten 1968, Taylor and Little 1950, and Wiggins and Thomas 1962). tree at each site. If no mature capsules were present on the tree, they were collected from the ground directly beneath. Hybrid index of herb- arium specimens was determined from whatever material was available — usually one to three aments. Collections were made during the summer of 1967 and 1968, whenever other fieldwork took us into different areas of Alaska. Most of the collections were concentrated along the roads of interior and southeast Alaska; samples were collected from 26 geographically separated stands. In addition, 21 specimens, collected by E. L. Little in 1961, were examined and given index numbers. These specimens, as well as our own, are on file in the herbarium at the Forestry Sciences Laboratory at College, Alaska. Twelve herbarium specimens from the University of Alaska were also classified by the hybrid index. Results The hybrid index numbers are mapped in Figure 2. Nearly pure populations of balsam poplar occur north of the Alaska Range, on the south slope of the Brooks Range, and in the Copper River basin. Pure populations of black Cottonwood are located along the coast of southeast Alaska and adjacent to Prince William Sound. Hybridization occurs in the Haines area, in the mountain pass between Valdez and the Copper River basin, and especially in the Cook Inlet region, the Matanuska Valley, and the Kenai Peninsula. Only one specimen was collec- ted from the Susitna River valley 10 miles south of the summit of the Alaska Range. This collec- tion, with an index value of 3, indicates that the Susitna valley is probably another region of Please note that these images are extracted from scanned page images that may have been digitally enhanced for re
Size: 1889px × 1323px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectnaturalhistory, booky
