As most of you know, I was in Nashville, Tennessee in October for the Natural Areas Association annual conference. I showed a few photos from my conference field trip at Botany Slide Show, but I thought you might like to see some of the photos that I didn't show.
Nashville is located in what is known as the Central Basin of Tennessee. While this natural region is now at a lower elevation than the surrounding Highland Rim, before being eroded it was at a higher elevation in the form of a dome. Caves and sinkholes are very common throughout the area.
We first visited a limestone barren. I expected something similar to the dolomite glades of Missouri, but this community was very different. I now understand why these areas are sometimes called "pavement."
One of the plants I was hoping to see on the limestone barrens was the Federally Endangered Dalea foliosa. I've seen this prairie clover on dolomite prairies near Chicago, so I wanted to compare the habitat and associate species. Unfortunately, our guides had not located any Dalea foliosa this year in the places it had been seen in past years. They thought it might have been due to weather conditions. When they showed us the place it had been seen in past years, I was surprised at how shrubby it was. I'm wondering if this rarity hasn't been shaded out at the site we visited.
While we didn't find Dalea foliosa, we did see Dalea gattingeri (but it wasn't flowering). While this species is not Federally or State listed, it is restricted to the limestone barrens of the southeastern US.
Also on the limestone barrens, Theo Witsell and I came across the tiny Scutellaria parvula.... not rare, but often overlooked because of its size.
After the limestone barrens, we visited a couple of cedar glades. As seen in the photo below, the cedar glades have the obvious presence of more grasses and Juniperus virginiana. It's hard to believe, but these communities have apparently not been fire-maintained.
One of the plants we saw in the cedar glades was Grindelia lanceolata. The genus is named for the Latvian botanist David Hieronymus Grindel (how about that for a middle name, Dana and Justin??). This isn't an uncommon plant, but it was one I'd never seen. I'm surprised to see that it's known from Wisconsin, as it seems to have more of a southern distribution overall. It would be interesting to compare the few remaining cedar glades in Wisconsin to those in the southeastern US.
Along a roadside near a cedar glade we saw the State Threatened Silphium pinnatifidum, or S. terebinthinaceum v. pinnatifidum. I'd only read about this gem in the past. It grows in cedar glades in scattered counties within Tennessee (and in a band from Wisconsin to Georgia).
If you've actually read this far, you're in luck. The next two species that we saw in the cedar glades are rare in Tennessee, and one of the two is endangered in the US.
Astragalus tennesseensis is listed as Special Concern in Tennessee, but it's only known from a handful of counties in the state on cedar glades and limestone barrens. Unfortunately, it flowers in the spring, so we were only able to find the remains of some fruit.
Lastly, Echinacea tennesseensis, Federally Endangered; the first species from Tennessee ever to be designated as Federally Endangered. This species is only known from three counties within one watershed in the Central Basin of Tennessee, even though plenty of appropriate habitat is present in other watersheds nearby. Where it is present, it is abundant. At the first cedar glade, we only found it in fruit.
Rain had started to fall pretty steadily by the time we arrived at the next cedar glade. I decided I would leave my camera in the bus, as I assumed we wouldn't find anything else exciting in flower. After a 1/2 mile walk, we arrived in an opening full of Echinacea tennesseensis, and several were still in flower. I took a few photos with my cell phone, but decided it was worth a jog back to the bus in the rain to get my camera. Well worth the exercise...