| Special Geographical Unit: | Apalachicola National Estuarine Sanctuary |
| Verbatim Directions to Locality: | M&K tract, W of Saul Creek North of M&K at junction Saul Creek road and Howard Creek road (rte 387), 7 mi E of [highway] 71 and ca. 13 air mi NE of Port St. Joe. |
| Plant Morphology Observations: | Plants decumbent with drooping inflorescenes, perianth greenish as in P. hydropiper, but seed lustrous. |