Before going on trips to collect seed, our team does research on every plant on our list so that we can understand what it looks like at every stage and be better prepared to identify it within the field. It usually takes quite a while to learn the key characteristics and the plants sometimes meld together in my mind. For some plants, they are so unique and unexpected that I am ecstatic to find them in the field. One such plant is the bottle gentian, Gentiana andrewsii. It has 5 fused petals, forming a tube that will never open. This closed tube resembles a closed bottle, thus the name.
While in northern Minnesota, the team saw one in the parking lot of our site and nowhere else. It is such an interesting inflorescence because it never opens. I could not imagine how it could be pollinated. After some outside research into the scientific literature, I learned that only bumblebees are physically able to crawl inside the tube and rub pollen on their sternum in the process. Oddly enough, the corolla tube of Gentiana andrewsii is much longer than the tongue of the two studied bumblebees. This would make it very difficult for bumblebees to access the nectar at the bottom. Instead, most bees access the nectar through lateral lacerations. The bees studied were not known for being corolla perforating species and no other mechanisms for lacerations were provided. Even as they steal nectar from some inflorescences, it was only observed coupled with also entering the tube to retrieve pollen. My theory is that the stealing is not driving changes on either side because the bees get nectar and the plants still get their pollen spread.
Gentiana andrewsii is a dependable species for bumblebees because no other pollinators are in competition for the resources. I was bummed that we did not find a large population, but future collections of this plant would be great for native bee restoration efforts!
Check out this video on Facebook of a bee diving head first into the plant.
Check out this amazing paper for more details!
Costelloe, B. H. (1988). Pollination ecology of Gentiana andrewsii. Ohio Journal of Science, 88(4), 132-138.