Why Correct: Phoenix paludosa, the mangrove date palm, is endemic to the Gulf Coastal Plain region of the southeastern United States, specifically found in coastal wetlands from Florida to South Carolina.
Distractor Analysis: Quercus incana (bluejack oak) has a wider distribution across southeastern US beyond just the Gulf Coastal Plain. Eleusine coracana (finger millet) originated in Africa and is cultivated worldwide. Kydia calycina is native to Southeast Asia and the Indian subcontinent.
Takeaway: Endemic species have restricted geographic ranges and are often vulnerable to extinction due to habitat loss or climate change in their limited habitats.