Plants of South Eastern New South Wales
Brassica nigra
Common name
Black Mustard
Family
Brassicaceae
Where found
Grassy areas, crops, roadsides, and waste areas. Mainly Sydney and within about 30 km of Bathurst. Occasionally elsewhere.
Notes
Introduced annual herb. Stems to 1 m high. Bristly at the base of the plant and becoming hairless above. Basal and lower leaves to 16 cm long, bristly on both sides, with 1–3 pairs of irregularly-toothed lobes. Stem leaves alternating up the stems, higher leaves entire, hairless, and often glaucous. Flowers bright yellow, with 4 petals each 7–9 mm long. Flowers in crowded clusters. Flowers Nov.-Jan. Seed cases erect and close to the stems, 1–2 cm long, (including the beak), 1–2 mm wide, 4-angled; slightly constricted between the seeds, midvein prominent. Beak 1–3 mm long, seedless. Stalk 3–8 mm long. Seeds dark red-brown.
PlantNET description: http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Brassica~nigra (accessed 6 January, 2021)
This identification key and fact sheets are available as a free mobile application:
