Lichens found onLarix lyalliiandPinus albicaulisin southwestern Alberta, Canada

摘要

Fifty-two species of lichens were found onLarix lyalliiParl. andPinus albicaulisEngelm. trees in 31 stands in the subalpine zone of the mountains of southwestern Alberta. The species belong to the following North American distributional elements: 25, Pan Boreal; 13, Arctic Boreal; 8, Cordilleran or Western Boreal; 2, Pan North American; 2, Eastern Boreal; and 1, uncertain.InLarix lyallii, quadrats occupying the lower 30ensp;cm of the trunk were characterized by aParmeliopsis hyperoptandash;P. ambiguandash;Cetraria pinastriunion whereas quadrats in a region 40ensp;cm deep, centered at 1.3ensp;m from the base, were occupied by aLetharia californicandash;Alectoria glabraunion. InPinus albicaulis, the lower quadrats were characterized by aParmeliopsis ambiguandash;Cetraria pinastrindash;Parmeliopsis hyperoptandash;Lecidea fuscescensunion whereas the upper were occupied by aParmelia sphaerosporellandash;Letharia californicandash;Lecanora variandash;Alectoria glabraunion.Forty-eight species occurred on the smooth to rough, more absorbent, bark ofPinus albicauliscompared with 32 found on the rough bark ofLarix lyallii.Succession followed four stages: (1) the invasion of appressed foliose lichens on the tree bases, (2) the appearance of crustose species on the lower four feet of the trunk, (3) the invasion of foliose species on the trunk and branches, and (4) the appearance of fruticose species.