Our article on the conservation genetics of Penstemon debilis has just been published as open access in the Journal of Systematics and Evolution.
Here’s the link to the article: Wolfe AD, McMullen-Sibul A, Tepedino VJ, Kubatko L, Necamp T, Fassnacht S (2014) Conservation genetics and breeding system of Penstemon debilis (Plantaginaceae), a rare beardtongue endemic to oil shale talus in western Colorado, USA. Journal of Systematics and Evolution. DOI 10:1111/jse.12100
The article describes our study on reproductive biology and conservation genetics of the populations that existed in the late 1990s. The species was Federally Listed as “Threatened” in 2011. There are only seven known populations of this species, all restricted to a narrow range of oil shale talus in Garfield County, Colorado. At least one of the populations has disappeared in the last ten years. The plants are endangered because of energy extraction activities, but there have been efforts made to conserve this rare species.
Penstemon debilis is endemic to oil shale talus, occurring on steep slopes at about 2500 m (8200 feet) elevation. Because it is on shifting talus, stems are buried and the plant can reproduce clonally by extending stems downslope. It’s one of the most beautiful species I’ve ever had the privilege of visiting and photographing. It can be very successful in the garden, and it certainly puts on a wonderful display of blooms.
Robert Nold says this about the species in his 1999 book, “Penstemons” – “The habitat may be the most frightening in North America: the penstemons are found on a steep, unstable slope that drops off to sheer cliffs hundreds of feet high; the plants themselves are only two inches (5 cm) high – much shorter than the distance one falls after one fatal misstep backward from viewing this diminutive plant.” I couldn’t have said it better myself!
Here are a few more photos of Penstemon debilis and the habitat in which it occurs. These images are from slide scans, so the quality isn’t quite as good as the ones I’m usually using on this site.