This diploid (2n = 34) is close to nutans, but generally distinct. It has a widespread western range, and extends into Ky. and Tenn. along major river valleys. It is typical of more open weedy habitats. C. brachypodum differs from nutans as follows (FNA 5, W): pedicels 2-15 mm long (versus 10-55 mm), equaling or shorter than capsules, often becoming deflexed proximally (versus longer than capsules, sharply deflexed distally); leaves 0.5-3.5 cm long (versus 1-8 cm).