Common Australian Garden Weeds

Cyperus involucratus

Scientific name: Cyperus involucratus Rottb.


Umbrella sedge (Cyperus involucratus) showing the numerous, large and leafy bracts below the inflorescence.


Close-up of the branched inflorescence (young) of umbrella sedge.


A more mature inflorescence of umbrella sedge that has taken on a reddish-brown colour.


Close-up of the branching inflorescence with clustered flower spikelets.


Close-up of the flower spikelets.

Synonym: Cyperus flabelliformis Rottb.

Common name:Umbrella sedge

Family: Cyperaceae

Origin:

Native of Africa.

Habit:

Perennial herb with 3-angled to almost cylindrical 45-120 cm tall stems carrying leafy bracts beneath clustered inflorescences, true leaves are reduced to long sheaths on the stems.

Habitat:

This plant was introduced as an ornamental, it has become naturalised in damp areas.

General description:

Stems and leaves

Stems are 3-angled to almost cylindrical, 3-5 mm thick and rigid. They are hairless and ridged longitudinally. True leaves are the long sheaths covering the base of the stems.

Flowers and fruit

The inflorescence has about eight (5-10 cm) stalks radiating from the top of the stem. There may be branching into secondary stalks 1-2 cm long. The oblong-linear spikelets are arranged in hemispherical clusters. At the base of the inflorescence is a whorl of 12-22 green leafy bracts up to 1.5 cm wide and greater in length than the branches of the inflorescence. Seeds are ochre, ellipsoid, triangular in cross-section, with a small ‘beak’ at the apex and about a millimetre long.

Distinguishing characteristics:

Reed-like plant with leaves reduced to sheaths. The green leafy inflorescences are up to 120 cm tall.

Noxious status:

Not noxious.

Sources:

Stanley, T.E. and Ross, E.M. (1983-1989). Flora of South-eastern Queensland. Volume 3. Department of Primary Industries, Brisbane.

Anonymous. (1994). Queensland Vacsular Plants: Names and Distribution. Queensland Herbarium, Brisbane.