A survey was made of the vascular flora at 36 sites in the area of lower Pool 26, Mississippi and Illinois rivers. A total of 239 taxa representing 73 families was recorded. Thirty-three plants from Jersey, Calhoun, and Madison counties in Illinois not previously listed as occurring in these counties in published material are noted. Boltonia asteroides (L.) L’Her. var. decurrens (Torr. and Gray) Engelm., a nationally threatened species, was found in Illinois, while a plant found in Missouri, Chelone obliqua L. var. speciosa Pennell & Wherry, is listed as a status undetermined species throughout that state.