Rediscovered in 1989 by N. Havlik on Grizzly Isl. in the Suisun Marsh; now known from two occurrences. Threatened by altered hydrology and competition from native and non-native plants. Potentially threatened by foot traffic and trampling by cattle. Protected in part at Grizzly Island WA and Peytonia Slough ER (both DFG). See Proceedings of the Academy of Natural Sciences of Philadelphia 44:358 (1892) for original description.