No plants meet the strict definition of “Endemic Plants of Maine.”
Understand that state-level endemism is a very narrow test. Endemism means a species occurs only inside a single, defined area. Use that test on Maine and you get no true matches. Maine shares its climate, soils, and habitats with neighbouring New Brunswick and New England. Plants do not follow political borders. Expect most species to cross into adjacent states and provinces.
Note the technical reasons behind this result. Maine was reshaped by the last ice age and recolonized from nearby refugia. That history, plus broad coastal and boreal habitats, reduces the chance of a species evolving only inside Maine. True endemics usually arise on isolated islands, unique soil outcrops, or long-isolated mountain tops. Maine has few landforms with that kind of long-term isolation. As a result, look for near-endemics and small-range specialists instead of strict state-only species.
Explore close alternatives and related categories that do exist. Search for near-endemics to the Acadian/New England region, alpine specialists on Mount Katahdin, coastal-dune plants of Casco Bay, and bog or peatland specialists. Also check lists of Maine “state-rare” and federally listed species. Consult authoritative sources for county-level ranges and conservation status: Maine Natural Areas Program, NatureServe, USDA PLANTS, and BONAP.
Instead of strict endemics, focus on near-endemic species, habitat specialists, and Maine’s rare-plant conservation priorities.
