Plants of
South Australia
Machaerina juncea
Blue Twig-rush,
Bare Twig-rush
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Regional Species Conservation Assessments per IBRA subregion.
Least concern
Near threatened
Critically endangered
Data deficient
Coober Pedy
Mount Gambier
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Botanical art

Kath Alcock paintings: 3

Prior names

Baumea juncea

Cladium junceum

Common names

Blue Twig-rush

Bare Twig-rush


Machaerina from the Latin 'machaera' meaning a bent dagger or sword, and the feminine diminutive suffix '-ina", referring to the shape of the leaves of some species (formally Baumea named after Antoine Baume (1728 - 1804), a French chemist and inventor). Juncea from the Latin 'juncus' meaning rush-like, alluding to its appearance and habit.

Distribution and status

Found in the southern part of South Australia, south of Port Augusta, with isolated occurrences in natural springs further north, growing mostly in brackish or saline swamps, on sandy soils. Also found in all states except in the Northern Territory. Native. Common in South Australia. Common in the others States.
Herbarium regions: Lake Eyre, Flinders Ranges, Eyre Peninsula, Northern Lofty, Murray, Yorke Peninsula, Southern Lofty, Kangaroo Island, South Eastern, Green Adelaide
AVH map: SA distribution map (external link)

Plant description

Slender perennial sedge with smooth, terete, stems to 100 cm high and 1 mm thick and 2- or 3-noded. Leaves all reduced to mucronate sheaths. Flower in small panicle, spike-like to 8 cm long with few, reddish-brown, densely crowded spikelets. Flowering September to April. Fruits are short golden brown heads at the tip of the stem. Seeds are reddish-black elliptical nut to 4 mm long and 3 mm wide, with a pitted surface. Seed embryo type is capitate.

Seed collection and propagation

Collect seeds between December and June. Collect whole fruiting heads that are brown, containing dark hard seeds. Not all heads will contain seeds. 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. Seed viability is variable depending on maturity of seeds when collected. This species is generally difficult to germinate, it has morphophysiological dormancy and complex germination requirements.