Gila nigra, the headwater chub, a fish species found in Arizona and New Mexico
Sambucus nigra | Centaurea nigra | Pinus nigra | Juglans nigra | Fraxinus nigra | Carex nigra | Brassica nigra | Populus nigra | Tinea nigra | Prosopis nigra | Porta Nigra | ''Populus nigra'', originating in the United States from plantings by André Michaux | M. nigra | Mined leaf of ''Centaurea nigra | Leaf of ''Ballota nigra | Hoplocorypha nigra | Gila nigra | Betula nigra | A shoot of ''Centaurea nigra |
Brassica nigra, the black mustard, an annual weedy plant cultivated for its seeds, which are commonly used as a spice
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Betula nigra, a species of birch native to the eastern United States from New Hampshire west to southern Minnesota, and south to northern Florida and east Texas
Hoplocorypha nigra, a praying mantis species found in the region of the Congo River
The SRV serotype-2 was found in endemic infections of pig-tailed monkey (M. nemestrina), cynomolgus macaques, Japanese macaque (M. fuscata), at Washington NPRC, and in rhesus and Celebes black macaques (M. nigra) at Oregon NPRC.