Family: Asteraceae
Centaurea nigra
Citation:
L., Sp. Pl. 911 (1753).
Synonymy: Centaurea nigrescens Common name: Black knapweed, hard-heads.
Description:
Perennial herb to 1 m high, with rhizomes; stems ascending, branched, ribbed, scabrous, slightly cobwebby; basal leaves oblanceolate, narrowed at the base, acute, 6-25 cm long, pinnatifid to entire with undulate margins, finely scabrous; cauline leaves lanceolate to oblong, acute, entire or with a few remote teeth, 1-8 cm long, 2-10 mm wide, scabrous-pubescent, sometimes cobwebby on the lower surface.
Capitula solitary; involucre broadly ovoid, 14-18 mm long; bracts ovate, glabrous; appendages obscuring the bracts, 2-3 mm long, deeply pectinate, dark-brown; outer florets erect to patent; corollas pale-purple.
Achenes c. 3 mm long, pale-brown, slightly ribbed; pappus of bristles to 1 mm long.
Published illustration:
Parsons (1973) Noxious weeds of Victoria, p. 91.
Distribution:
|
On roadsides and waste land.
S.Aust.: MU. Vic. Native to Europe.
|
Conservation status:
naturalised
Flowering time: most of the year.
|
SA Distribution Map based
on current data relating to
specimens held in the
State Herbarium of South Australia
|
Biology:
C. pratcrisis Thuill. is apparently a hybrid between C. nigra and C. jacea L. It was recorded in S. Aust. near Sevenhills in 1934 but has not been collected since then.
Author:
Not yet available
|