Hygrophila sandwithii Hygrophila sandwithii Bremek. in Bull. Misc. Inform. Kew 1939: 559. 1940 sec. D.C. Wasshausen & al. 2005Isotype: Guyana, Mazaruni Station, Sandwith 1546Holotype: Guyana, Mazaruni Station, Sandwith 1546