Allopatric hybridization and introgression between Juniperus maritima R. P. Adams and J. scopulorum Sarg. II. Additional Evidence from nuclear and cpDNA genes in Montana, Wyoming, Idaho and Utah

A previous study using data from nrDNA (ITS), maldehy, and petN-psbM (cpDNA) confirmed that allopatric hybridization is occurring at Wallowa, OR, eastern WA, and southeastern BC into western Montana. nrDNA was found to be of less use in detecting hybrids than a single copy nuclear gene (SCN), maldehy. This might to be due to concerted evolution in nrDNA or relictual effects from ancient speciation. The uniform presence of either J. maritima cpDNA in western BC and WA or J. scopulorum cpDNA in eastern BC, WA, OR, and MT suggests allopatric introgression by air-borne pollen. Juniperus trees in the study area can be divided into roughly four zones: 1. typical J. maritima: Puget Sound, Vancouver Island, islands in the Strait of Georgia, and western BC; 2. intermediate trees: eastern WA, Wallowa, OR, southeastern BC, and western MT; 3. trees introgressed from J. maritima into J. scopulorum: Montana and northeastern Wyoming; 4. mostly typical J. scopulorum: south eastern ID, Utah and southward in the Rocky Mtns. Published on-line www.phytologia.org Phytologia 97(3): 187199 (July 1, 2015). ISSN 030319430.