| Abstract | The volatile oils of the leaves and twigs of alpine fir, and western and eastern Canadian balsam fir were analyzed by gas–liquid chromatography. Many qualitative similarities were found and the within-tree and tree-to-tree variation of the quantitative terpene composition of the leaf oil was sufficiently small to permit a chemosystematic study. Abies lasiocarpa and A. balsamea may be differentiated by the relative amounts of β-pinene, 3-carene, β-phellandrene, trans-ocimene, piperitone, methyl thymol, and thymol. Consistent quantitative differences were also found between eastern and western A. balsamea, and the populations in the Lesser Slave Lake and Battle Lake regions of central Alberta gave intermediate terpene data, which suggests introgression between A. lasiocarpa and western A. balsamea. Thus a cline between A. lasiocarpa and A. balsamea, with western balsam fir populations as bridge, may have existed after the last glaciation. The alpine fir populations of southern Alberta, and eastern and central British Columbia gave uniform terpene data, but five trees sampled on Green Mountain, Vancouver Island, gave significantly different terpene data. These results were substantiated by morphological characters as well as twig oil analysis, but the latter two methods gave less consistent data than leaf oil analysis. |
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