bidens genus -- Aster subfamily 3.1

​Aster 3.1 (Genus A to F) -- Aster 3.2 (Genus G to O) -- Aster 3.3 (Genus P to R) -- Aster 3.4 (Genus S to Z)  

nodding beggartick (Bidens cernua) -- in August -- Redwing Marsh, Fort Collins Natural Area, Larimer County, CO

nodding beggartick (Bidens cernua) -- in August -- East Boulder Community Park, Boulder County, CO