I am still trying to sort through the correct name of this species (forgive me: it’s true I don’t have all 400 species figured out quite yet. Touché!). For now, I’m calling it Ruellia angustior. Regardless of such a minor point, this was a remarkable plant that we encountered in the campos rupestres and cerrados of Goiás, Brazil, where it turned out to be NOT uncommon, but not frequent.
Unique among this species compared to all others I have learned and studied in the field is that, as the corolla senesces, it separates / breaks apart near that halfway mark of the narrow unexpanded portion of the tube. The lower half stays attached to and envelopes the ovary through fruit maturation. Perhaps some sort of adaptation against seed predation? Incidentally, finding fruits that are entirely predated by small maggots and finding whole populations infected by said seed predators is rampant among Neotropical Ruellia and makes me sad (it’s true)!
Wild collected, Brazil, Erin Tripp #5926, 5929, & 5935 w/ Nico Medina, Cíntia Kameyama (COLO); Photos by Erin Tripp, Nico Medina