black mangrove has 2 distinct synonyms spread across 2 of its 2 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. WordNet records no antonym for it — antonymy is a relation between word forms rather than concepts, so it is deliberately sparse.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
an Australian tree resembling the black mangrove of the West Indies and Florida
a mangrove of the West Indies and the southern Florida coast; occurs in dense thickets and has numerous short roots that bend up from the ground
Synonyms, antonyms and the broader and narrower relations for black mangrove come from Princeton University’s WordNet. Full sources and licences.