| County | Township | Location | Institution | Year | Month | Day |
| York | York | Cape Neddick, southern ME | University of New Brunswick Fredericton (UNB(CEMAR)) | 2006 | 11 | 3 |
| Washington | Machiasport | End of public road, Starboard | University of New Brunswick Fredericton (UNB(CEMAR)) | 2006 | 4 | 25 |
| York | York | Cape Neddick, southern ME | University of New Brunswick Fredericton (UNB(CEMAR)) | 2006 | 4 | 24 |
| York | Kittery | Appledore Island, dive off pilings by Machine Shop, Isles of Shoals, SCUBA, Kittery, ME | University of South Florida (USF) | 1978 | 7 | 10 |
| Washington | Beals | Great Pond, Great Wass Island, Washington Co. | University of Maine Herbaria (MAINE) | 1975 | 7 | 3 |
| Lincoln | Westport Island | Clough Pt., Westport Is., Sheepscot River | University of Maine Herbaria (MAINE) | 1967 | 4 | 28 |
| Lincoln | Bristol | Salt Pond, New Harbor, Lincoln Co. | University of Maine Herbaria (MAINE) | 1967 | 2 | 12 |
| Washington | Lubec | Quoddy Head, Lubec, Washington Co. | University of Maine Herbaria (MAINE) | 1966 | 4 | 3 |
| Lincoln | Bristol | John's Island, Bristol, Lincoln Co. | University of Maine Herbaria (MAINE) | 1964 | 9 | 21 |
| Knox | Friendship | Penobscot Bay, Otter Island | The New York Botanical Garden (NY) | 1929 | 7 | 2 |
| York | York | York Harbour | Drexel University, Academy of Natural Sciences (PH) | 1909 | | |
| Cumberland | Portland | Peak's Island | The New York Botanical Garden (NY) | 1904 | 5 | 21 |
| Lincoln | Bristol | Pemaquid Point, Bristol, ME | University of Connecticut (CONN) | 1901 | 7 | 18 |
| Lincoln | Bristol | Pemaquid Point | The New York Botanical Garden (NY) | 1901 | 7 | 18 |
| Cumberland | Portland | Portland, ME | Yale University Herbarium (YPM-YU) | 1866 | | |