<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="6.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Dugle, J. R.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">A taxonomic study of western Canadian species in the genus Betula</style></title></titles><dates><year><style  face="normal" font="default" size="100%">1966</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://article.pubs.nrc-cnrc.gc.ca/RPAS/RPViewDoc?_handler_=HandleInitialGet&amp;calyLang=eng&amp;journal=cjb&amp;volume=44&amp;articleFile=b66-106.pdf</style></url></web-urls></urls><publisher><style face="normal" font="default" size="100%">Canadian Journal of Botany</style></publisher><volume><style face="normal" font="default" size="100%">44</style></volume><pages><style face="normal" font="default" size="100%">929-1007</style></pages><language><style face="normal" font="default" size="100%">en</style></language><abstract><style face="normal" font="default" size="100%">Five western North American birches, Betula fontinalis, B. glandulosa, B. glandulifera, B. resinifera, and B. papyrifera, are studied taxonomically. Four hybrids, B. × winteri, B. × sargentii, B. × arbuscula, and B. × uliginosa, are described for the first time and three others, B. × utahensis, B. × eastwoodae, and B. × sandbergii, are also included. Populations formed when species are in contact have been analyzed and the nature of several hybrid entities determined. B. × uliginosa results from B. resinifera × B. glandulifera. In this population, introgression is toward B. glandulifera, which has the higher chromosome number. B. glandulifera also hybridizes with B. glandulosa producing B. × sargentii. Most gene flow is toward B. glandulifera, which has the higher chromosome number. In B. glandulosa × B. fontinalis (B. × eastwoodae) introgression was little influenced by environmental selection, the hybrid was as common as either parental species, and any gene flow was in either direction. B. × utahensis results from B. papyrifera × B. fontinalis. Introgression is toward B. papyrifera. Hybridization of B. × sargentii and B. papyrifera produces B. × arbuscula, a rare hybrid. Hybridization of B. resinifera and B. papyrifera results in B. × winteri, with introgression in both directions. B. × sandbergii results from B. papyrifera × B. glandulifera. Probably as a result of environmental influence in the analysis area, introgression was toward B. glandulifera, with the lower chromosome number.</style></abstract><custom1><style face="normal" font="default" size="100%">Forestry</style></custom1><custom2><style face="normal" font="default" size="100%">Coalbranch, Edson, Jasper National Park</style></custom2><custom3><style face="normal" font="default" size="100%">http://www.worldcat.org/oclc/421468387</style></custom3><custom4><style face="normal" font="default" size="100%">Science</style></custom4></record></records></xml>