Bidens micrantha is a species of flowering plant in the aster family known by the common name grassland beggarticks. It is endemic to the Hawaiian Islands, where it and other Bidens species are known as kōʻokoʻolau. It occurs in many types of habitat on Lānaʻi, Maui, and Hawaiʻi, including rocky cliffs, dry forests, mesic forests, wet forests, and high shrublands.SubspeciesB. m. ssp. micrantha (Maui) B. m. ssp. ctenophylla (Sherff) Ganders & Nagata B. m. ssp. kalealaha Ganders & Nagata