salix nigra(n = noun.plant) black willow, swamp willow - North American shrubby willow having dark bark and linear leaves growing close to streams and lakes;
is a kind of willow, willow tree
is a member of genus salix, salix

ballota nigra, betula nigra, brassica nigra, centaurea nigra, ciconia nigra, dalbergia nigra, fraxinus nigra, genus salix, juglans nigra, melanitta nigra, morus nigra, nigra, phyllostachys nigra, pinus nigra, populus nigra, populus nigra italica, prunus nigra, quercus nigra, salix, salix alba, salix alba caerulea, salix alba sericea, salix alba vitellina, salix amygdalina, salix amygdaloides, salix arctica, salix babylonica, salix blanda, salix candida, salix caprea, salix cinerea, salix discolor, salix fragilis, salix herbacea, salix humilis, salix lasiolepis, salix lucida, salix pendulina, salix pendulina blanda, salix pentandra, salix purpurea, salix pyrifolia, salix repens, salix sericea, salix sitchensis, salix triandra, salix tristis, salix uva-ursi, salix viminalis, salix vitellina, sambucus nigra, substantia nigra