Aaron Wenzel, one of my graduate students, is studying the Caespitosi group of Penstemons in the Rockies and Intermountain region. He had never seen a Dasanthera group penstemon, and we found P. davidsonii on the summit of Mount Ashland. We hiked up from a spot a mile or two below the summit. There was still snow on the road, closing the area to automobile traffic.
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This is a macro shot of Penstemon davidsonii.
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The Siskiyous is an interesting mountain range in southern Oregon. There is a lot of biodiversity to be found here, partly because the region was a glacial refugium during the Pleistocene.
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We saw many different species of Penstemon. This is a macro of P. deustus, aka Hot Rock Penstemon.