Bladder ketmia, also known as Hibiscus trionum, is a small annual plant commonly found in North America. Its yellow flowers have a unique bladder-like structure. Bladder ketmia also goes by the names of flower-of-an-hour, Venice mallow, and bladder hibiscus. The plant is sometimes confused with the more commonly known Hibiscus plant, but they are not the same species. Flower-of-an-hour is a reference to the plant's impressive blooming cycle, with flowers opening in the morning and closing within a few hours. Venice mallow comes from the plant's Mediterranean origin. Bladder hibiscus is a more straightforward description that refers to the plant's characteristic bladder-shaped seed pods.