I'd not seen these gentians in many years, and have been fortunate to twice renew my acquaintance with them over the past week or so. This state-endangered species is known only from a few locales within the Oak Openings of Lucas County, a globally rare ecosystem full of imperiled flora and fauna. While I've made scores of visits to the Oak Openings over the years, I'd not spent much time there recently, and needed to atone for that.
I had really hoped to catch a bee in the act of pollinating one of these gentians, but no such luck. You may wonder what the enticement is for the bee to go to fairly great lengths to enter the flower. Well, the inside of the plaits are boldly striped with colorful lines - nectar guides - and the bee sees those through the exterior of the bloom. Their visual allure is great, and the bee eventually forces its way inside, and then contacts the pollen, gets a dusting, and also deposits pollen from previous visits on the flower's stigma, or female parts.