Closed Gentian (Gentiana andrewsii) was always a puzzle to me. When I first saw a picture of it in a field guide, I assumed that the photographer had simply taken the picture before the petals fully opened up. It was many years before I finally figured out what this plant’s deal was.
Back in 2004, while doing field work out at the Tall Grass Prairie Preserve, I had to walk past a few Closed Gentian plants to get to my research plots where I was studying pollinators. Every day I would think to myself, “when are those flowers finally going to open up?” Then one day as I walked past one, the whole plant vibrated. I paused, waiting to see what was going on. Suddenly, one of the fattest bumblebees I’ve ever seen pushed its way out of the flower and flew to another one, pausing briefly to nibble a small hole in the tip before pushing her way in. The proverbial light bulb went off in my head: the closed petals was this gentian’s way of preventing small insects that may be less-effective pollinators, from getting its precious nectar and pollen. Brilliant! I even came across a great video showing this behavior (https://www.youtube.com/watch?v=vDCrQzojP84).
Although there are many plants in the tropics that rely on very specific pollinators, this phenomenon is less common in Canada: most plants here rely on a wide range of pollinators-bees, flies, butterflies, moths and beetles-some over a hundred species. However, the only other type of pollinator besides bumblebees that can visit Closed Gentian are hummingbirds, which stick their long bills into the tip of the flower to access the nectar.
I was so delighted with this plant that, many years ago, I asked our Diorama Artist to create a model of it, complete with a bumblebee butt sticking out, for a temporary exhibit on pollination I was doing. My plan was to eventually put this model in a permanent exhibit. At long last this lovely model will finally be on display in an exhibit on pollination, along with a hovering hummingbird, when the new Prairies Gallery opens up this fall.