Plants of
South Australia
Cyperus bulbosus
Cyperaceae
Bush Onion,
Bulbous Flat-sedge
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Adelaide
Arkaroola
Ceduna
Coober Pedy
Hawker
Innamincka
Marla
Marree
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Oodnadatta
Renmark
Wudinna
Keith
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Botanical art

Kath Alcock paintings: 5

Prior names

Cyperus andrewsii

Common names

Bush Onion

Bulbous Flat-sedge

Etymology

Cyperus from the Latin 'cyperos' and derived from the Greek 'kypeiros', an ancient Greek name used by Homer and Theophrastus for several plants of this genus. Bulbosus from Latin meaning bulbous, referring to the numerous ovoid bulbils at the ends of the rhizomes.

Distribution and status

Found in north-east South Australia growing on sand near claypans. Also found in Western Australia, Northern Territory, Queensland and New South Wales. Native. Common in South Australia. Common in the other States.
Herbarium regions: North Western, Lake Eyre, Gairdner-Torrens, Flinders Ranges, Eastern
NRM regions: Alinytjara Wilurara, South Australian Arid Lands
AVH map: SA distribution map (external link)

Plant description

Perennial sedge to 35 cm high, producing numerous ovoid shining bulbils at the ends of the rhizomes, the latter very soon disintegrating. Stems slender, triquetrous. Leaves numerous, almost setaceous, about as long as the stem. Inflorescence of rather few spikelets arranged in a simple or compound spike or short corymb, with the rays and bracts distant from one another, one or more of the lower bracts longer than the inflorescence. Spikelets reddish to pallid, linear or somewhat lanceolate to 30 mm long and 2 mm wide, with 10-28-flowers. Flowering between April and July. Fruits are reddish-brown loose spike. Seeds are dark brown oblong triangular seed to 1.8 mm long and 0.6 mm wide, with fine tuberculated surface. Seed embryo type is capitate.

Seed collection and propagation

Collect seeds between June and October. Collect fruits by picking off the mature heads, those turning brown colour and come-off easily. Place the heads in a tray and leave to dry for one to two weeks. Then rub the heads with a rubber bung to dislodge the seeds. Use a sieve to separate any unwanted material. Store the seeds with a desiccant such as dried silica beads or dry rice, in an air tight container in a cool and dry place.

Seeds stored:
  Hide
LocationNo. of seeds
(weight grams)		Number
of plants		Date
collected		Collection number
Collection location		Date
stored		% ViabilityStorage
temperature
 
MSB
4,600 (1.43 g)		50+3-Apr-2007RJB71180
Eastern
Location: BGA — the seeds are stored at the Adelaide Botanic Gardens, MSB — the seeds are stored at the Millennium Seed Bank, Kew, England.
Number of plants: This is the number of plants from which the seeds were collected.
Collection location: The Herbarium of South Australia's region name.
% Viability: Percentage of filled healthy seeds determined by a cut test or x-ray.
We acknowledge the contributions of the South Australian Seed Conservation Centre, the Botanic Gardens of South Australia, and the Department for Environment and Water.