Brassica nigra
black mustard
usually branched distally, (widely spreading), 3–20 dm.
petiole to 10 cm;
blade lyrate-pinnatifid to sinuate-lobed, 6–30 cm × 10–100 mm, lobes 1–3 each side, (smaller than terminal, terminal lobe ovate, obtuse).
sessile or subsessile;
blade (ovate-elliptic to lanceolate, similar to basal, reduced distally and less divided), base tapered, not auriculate or amplexicaul, (margins entire to sinuate-serrate).
not paniculately branched.
sepals 4–6(–7) × 1–1.5 mm;
petals yellow, ovate, 7–11(–13) × (2.5–)3–4.5(–5.5) mm, claw 3–6 mm, apex rounded;
filaments 3.5–5 mm;
anthers 1–1.5 mm.
erect (straight), (2–)3–5(–6) mm.
erect-ascending (± appressed to rachis), smooth, ± 4-angled, 1–2.5(–2.7) cm × (1.5–)2–3(–4) mm;
valvular segment 2–5(–8)-seeded per locule, (0.4–)0.8–2(–2.5) cm, terminal segment seedless (linear, narrow), (1–)2–5(–6) mm.
brown to black, 1.2–1.5(–2) mm diam.;
seed coat coarsely reticulate, minutely alveolate, not mucilaginous when wetted.
= 16.
Brassica nigra
Brassica nigra is widely cultivated as a condiment mustard. It is also a cosmopolitan weed especially common in the valleys of California (R. C. Rollins 1993). It occurs only sporadically in southern Canada but most frequently in Ontario and along the St. Lawrence River. Specimens from Alberta, Arkansas, Delaware, and South Carolina have not been observed.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
- Local floras:
BC, 
CA, 
OR, 
WA - Local Web sites: CalFlora, CalPhotos,
Flora NW, 
Go Botany, 
IL Wildflowers, 
KS Wildflowers, 
LA Plants, 
MD Biodiversity, 
MI Flora, 
MN Wildflowers, 
MO Plants, 
PNW Herbaria, Turner Photog. 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
