Penstemon linarioides is a species native to the “Four Corners” states of Arizona, Colorado, New Mexico, and Utah (and a little bit into southern Nevada). The ascending-to-erect stems distinguish this species from other species in Penstemon section Ericopsis (like the mat-forming P. caespitosus or P. thompsoniae). In addition, P. linarioides has more described subspecies or varieties than any other species in section Ericopsis. The established taxonomy of these subspecies is based on morphological characters; however, my goal is to use putatively neutral microsatellite DNA markers to see if genetic data also distinguishes these subspecies from one another. I left Columbus in late May to set out on a two week journey with the goal of collecting as many populations as possible of each subspecies. First up on my list was subspecies coloradoensis, native to southwestern Colorado and northwestern New Mexico.
Subsp. coloradoensis tends to be both smaller and has a staminode that has a thinner beard than subspecies linarioides. With the help of Al and Betty Schneider of Southwest Colorado Wildflowers, I was able to make several collections and see some of the beautiful sites of the area around Cortez and Mesa Verde National Park in southwest Colorado.
The coolest thing, however, might have been the rattlesnake we encountered in Mesa Verde. As I was leaning over to look at a population of P. linarioides coloradoensis, this guy slithered through the thick oak brush that lines both sides of the Prater Ridge trail.
Subsp. linarioides, native to western New Mexico and eastern Arizona, is a bigger plant than coloradoensis. Interestingly, the corollas of this subspecies can have a very light violet, almost white color, which is very peculiar for members of Ericopsis.
Subsp. compactifolius, native to the area around Flagstaff, Arizona, is a smaller plant, distinguished by having leaves more compactly arranged on the stem (hence its name).
Of course, a huge perk of doing fieldwork in western North America (especially for a Midwestern boy!) is the plethora of views you have to look at. On my second-to-last day in Arizona I spent half a day at the Grand Canyon, by far the most majestic landscape I have ever personally seen.
The Grand Canyon roughly marks the southern range of the fourth subspecies, sileri, which stretches into southern Utah. I actually found some growing near the welcome center of the Grand Canyon National Park.
Subspecies sileri is similar to subsp. linarioides except that it has leaf pubescence that is flatly appressed to the leaf instead of standing more-or-less upright. Additionally, in Intermountain Flora, Noel Holmgren hypothesizes that there are several geographical races that have been lumped into sileri: a “mountain form” from the Pine Valley Mountains in southwest Utah that has more erect stems, and a “plateau form” from the Markagunt and Paunsaugunt plateaus with shorter, less erect stems. I want to use our Penstemon microsatellites to test this hypothesis for sileri.
Spending time in the Canyonlands of Utah is quite enjoyable. One of my favorite places I have spent time in during all of my field seasons is Red Canyon, close to Bryce Canyon, in southern Utah
It should be mentioned that there is one more subspecies of P. linarioides, subsp. maguirei, native to the Gila River valley of western New Mexico and eastern Arizona. However it has not been collected (nor seen) since 1995. Indeed, the type specimen for maguirei was collected in what is now a gigantic mine near Morenci, Arizona. I have spent two days over the past two field seasons searching for it and have not found it, nor have any botanists from the region I have contacted found it. And it is a shame, as with its oblanceolate leaves (instead of linear), which makes it an oddball for P. linarioides, it would have been very interesting to see what genetic data revealed about maguirei and its relationship to the other subspecies within P. linarioides.
Driving back from Utah I stopped again in Colorado, this time in the Gunnison Basin. Crested Butte is a picturesque ski town about thirty miles north of the city of Gunnison and is also about a thousand feet higher in elevation relative to Gunnison, making it several degrees cooler.
Overall my field season was a huge success. As always I am thankful that I get to do fieldwork in such beautiful places. And I hope that my efforts this summer will be useful in exploring the questions of the interesting, yet often problematic, Penstemon linarioides.