McGlaughlin, Mitchell

Committee Member

Reinsvold, Robert J.

Committee Member

Dawson, Carol


Biological Sciences


University of Northern Colorado

Type of Resources


Place of Publication

Greeley (Colo.)


University of Northern Colorado

Date Created





117 pages

Digital Origin

Born digital


Penstemon harringtonii is an endemic Colorado species that is listed on Bureau of Land Management (BLM) State Director’s Sensitive Species List as well as on the U.S. Forest Service sensitive species list. Penstemon harringtonii is encountering threats from habitat destruction and fragmentation due to oil and gas exploration, livestock grazing and recreational activities. Penstemon harringtonii is scattered across six counties in north central Colorado. The populations split into three general areas, one around Eagle and north to Kremmling, from Glenwood Spring south to Aspen and around the community of Rifle. The disjunct nature of the species has raised questions related to the amount of genetic diversity throughout the range, population structure dynamics and rates of gene flow among populations and regions. Individuals from 20 populations of P. harringtonii and 6 populations of Penstemon osterhoutii were collected from wild populations. Additional samples of P. osterhoutii, P. cyathophorus, P. secundiflorus, and P. angustiflolius were taken from herbarium specimens or live collections in botanic gardens. Microsatellite analysis was completed using 9 variable loci to determine genetic diversity, rates of gene flow and population structure of P. harringtonii. Chloroplast DNA analysis was completed using three intergenic regions to determine haplotype diversity, phylogenetic relationships and patterns of maternal gene flow. These analysis showed that P. harringtonii is distinct from P. osterhoutii. Three distinct genetic groups are present in P. harringtonii: Rifle, Roaring Fork River Valley and East of Glenwood Canyon. High levels genetic diversity are present with exceptional level of gene flow between genetic groups, which is great enough to maintain a cohesive species across the entire range. Inbreeding levels were low, posing minimal concern. Two population of P. harringtonii were found to be quite distinct at the northern and southern extents of the population when compared to the region genetic groups. Conservation and land management agencies now have genetic information that can be utilized to inform decisions about the conservations of P. harringtonii.

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