]> GH barcode-00466776 United States of America Oklahoma Big Springs at the headwaters of Spring Creek, 2.5 miles NE of Reagan, SE1/4 Sec. 18, T2S, R6E Callitriche heterophylla Pursh Pursh 2020-02-25 19:54:22 C. B. Hellquist & L. Crouch