| County | Township | Location | Institution | Year | Month | Day |
| York | Kittery | Appledore Island, South Side, near blocks and docks, Isles of Shoals, Kittery, ME | University of South Florida (USF) | 1978 | 7 | 2 |
| Cumberland | Harpswell | Harpswell Floating | Canadian Museum of Nature, Ottawa (CANA) | 1906 | 7 | 6 |
| Cumberland | Harpswell | Harpswell | University of Michigan (MICH) | 1906 | 7 | 6 |
| Cumberland | Harpswell | Harpswell, ME | Brown University (BRU) | 1906 | 7 | 6 |
| Cumberland | Harpswell | Harpswell | Field Museum of Natural History (F) | 1906 | 7 | 6 |
| Cumberland | Harpswell | Floating, Harpswell, Maine | Farlow Herbarium (Harvard University) (FH) | 1906 | 7 | 6 |
| Cumberland | Harpswell | Harpswell, Me [Maine] | University of North Carolina at Chapel Hill Herbarium (NCU) | 1906 | 7 | 6 |
| Cumberland | Harpswell | floating | The New York Botanical Garden (NY) | 1906 | 7 | 6 |
| Cumberland | Harpswell | Harpswell | Oregon State University (OSC) | 1906 | 7 | 6 |
| Cumberland | Harpswell | Harpswell, ME | Yale University Herbarium (YPM-YU) | 1906 | 7 | 6 |
| Cumberland | Harpswell | Harpswell | Michigan State University (MSC) | 1906 | 7 | 6 |
| Cumberland | Harpswell | Harpswell | Miami University (MU) | 1906 | 7 | 6 |
| Cumberland | Harpswell | Harpswell, Maine | University Herbarium, University of California, Berkeley (UC) | 1906 | 7 | 6 |
| Cumberland | Harpswell | Harpswell, Maine | University Herbarium, University of California, Berkeley (UC) | 1906 | 6 | 7 |
| Cumberland | Harpswell | dredged | The New York Botanical Garden (NY) | 1905 | 7 | |
| Cumberland | Harpswell | So. Harpswell, on stipe of Laminaria longicruris | The New York Botanical Garden (NY) | 1904 | 7 | |
| Cumberland | Harpswell | Harpswell, Maine | University Herbarium, University of California, Berkeley (UC) | 1903 | 7 | 3 |
| Cumberland | Harpswell | South Harpswell On a stipe of Laminaria longicruris | Canadian Museum of Nature, Ottawa (CANA) | 1903 | 7 | 1 |
| Cumberland | Harpswell | So. Harpswell | University of Michigan (MICH) | 1903 | 7 | |
| Cumberland | Harpswell | South Harpswell, ME | Brown University (BRU) | 1903 | 7 | |
| Cumberland | Harpswell | South Harpswell | Field Museum of Natural History (F) | 1903 | 7 | |
| Cumberland | Harpswell | South Harpswell, ME | Yale University Herbarium (YPM-YU) | 1903 | 7 | |
| Cumberland | Harpswell | South Harpswell | Michigan State University (MSC) | 1903 | 7 | |
| Cumberland | Harpswell | South Harpswell | Miami University (MU) | 1903 | 7 | |
| Cumberland | Harpswell | So. Harpswell, on stipe of Laminaria longicruris | The New York Botanical Garden (NY) | 1903 | 6 | |
| Cumberland | Harpswell | Harpswell, Maine | University Herbarium, University of California, Berkeley (UC) | 1903 | 3 | 7 |
| Cumberland | Harpswell | South Harpswell | The New York Botanical Garden (NY) | 1902 | 7 | 16 |
| Hancock | Deer Isle | Eagle Island | The New York Botanical Garden (NY) | 1896 | 7 | 0 |
| Washington | Eastport | [no additional data] | Farlow Herbarium (Harvard University) (FH) | 1877 | 9 | 0 |
| Hancock | Deer Isle | Eagle Island, Penobscot Bay, ME | University of Connecticut (CONN) | 0 | 0 | 0 |
| Cumberland | Portland | Portland Harbor | The New York Botanical Garden (NY) | 0 | | |