Plants of South Eastern New South Wales

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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)