Plantago Pollen

Plantago is a cosmopolitan genus of herbaceous (non-woody) plants that occur on all continents except Antarctica. The are about 200 species in the genus with 11 species native to or naturalized in Oklahoma. The common names for these plants are plantains (unrelated to the variety of cooking banana with the same name). The flowers, which are small and inconspicuous, are borne on a dense spike. 

Various Plantago species utilize different methods of pollination including self-pollination, wind, insects, or both. Plantago pollen grains are periporate, with an operculum within each pore, and 20-25 µm in diameter. The pollen is seen in Tulsa air samples from April through July.