Target Species: Creeping Bluestar (Amsonia repens)
Admittedly, I didn’t know much about Amsonia repens when I put it on my 2017 list of biodiversity goals. I knew that it was an showy wildflower that was endemic to the West Gulf Coastal Plain. This alone piqued my interest and prompted me to make it a target species.
What I found, however, was a general lack of information on the species. I struggled to find a good reference with information on how to differentiate it from the very similar A. tabernaemontana. I was able to track down some historic locations, however not feeling comfortable in my ability to identify it, I failed to pursue it with much enthusiasm. I stopped at a couple of sites in 2017 where a friend had reported some a few years prior but found nothing. After that, the species went on the back burner while I pursued other more easily researched species on the list.
What drew me to the Creeping Bluestar was its range, which is almost entirely confined to the eastern third of Texas. I have always had a strong interest in species endemic to the West Gulf Coastal Plain, which includes East Texas, western Louisiana, and extreme southeastern Oklahoma and southwestern Arkansas. There are a number of species that are restricted in range to this area, and this distributional pattern has long fascinated me.
My interest in pursuing Amsonia repens was renewed after I photographed some Amsonia plants in bloom in remnant prairie and marsh patches in Fort Bend and Brazos County this spring. I tried once again to do some research and came across a paper that was published in March of 2019: Taxonomy of the Amsonia tabernaemontana complex (Apocynaceae:Rauvolfioidae) by J K Williams from Sam Houston State. Though this paper proposes that A. repens be considered a variety of A. tabernaemontana, it provides the best treatment I have seen on differentiating A. repens from other similarly structured congeners.
In a nutshell, A. repens (or A. tabernaemontana var. repens) is best differentiated from A. tabenaemontana by having tomentose (hairy) calyces, a feature which can be seen in the image below.
Interestingly, after reading this paper and reviewing other taxonomic keys, I went back to examine some photos of Amsonia that I took in Montgomery County a few years ago and found that they too were A. repens. It had been hiding under my nose this whole time!