Common Australian Garden Weeds

Cotula australis

Scientific name: Cotula australis (Sieber ex Sprengel) J.D. Hook


Habit of common cotula (Cotula australis).


Another photo of this species with immature and mature flower-heads.


Close-up of the stem (with covering of soft hairs) and leaves (with highly dissected margins). 


Close-up of the globular flower-head of common cotula.

Synonym: Anacyclus australis Sieber ex Sprengel

Common names: Common cotula, Carrot weed

Family: Asteraceae

Origin:

Native of Australia.

Habit:

Annual or perennial herb, low growing, with stalked flower heads taller than the foliage.

Habitat:

Native species but a widespread weed of suburban bushland, parks, beaches, gardens and lawns thriving in damp shady areas.

General description:

Stems and leaves

Stems are prostrate and softly hairy with either long or short hairs. Leaves have stalks (petioles) 1-10 mm long, highly divided leaf blades 2 cm x 1 cm (1-2 pinnate) with leaflets usually less than 1 mm wide.

Flowers and fruit

Flower-heads have no ‘petals’ (rays) and are 3-6 mm in diameter, borne on erect stalks 1-6 cm long. Each flower head has 3-4 rows of female outer florets without corollas surrounding central bisexual florets with 4-lobed corollas. Seeds are of 2 types. The female florets produce a flattened, winged fruit borne on a distinct stalk while the bisexual florets produce wingless fruits on very short stalks. The seeds of both types are 1 mm long. Flowering occurs late autumn to spring.

Distinguishing characteristics:

Low growing herb with carrot-like leaves with greenish-white petal-less flower heads borne on erect stalks.

Noxious status:

Not noxious.

Sources:

Kleinschmidt, H.E., Holland, A. and Simpson, P. (1996). Suburban Weeds. 3rd Edition. Department of Primary Industries, Brisbane.

Stanley, T.E. and Ross, E.M. (1983-1989). Flora of South-eastern Queensland. Volume 2. Department of Primary Industries, Brisbane.