Plants of
South Australia
Baumea rubiginosa
Cyperaceae
Soft Twig-sedge
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Regional Species Conservation Assessments per IBRA subregion.
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Etymology

Baumea named after Antoine Baume (1728–1804), a French chemist and inventor. Rubiginosa means rusty-reddish colour.

Distribution and status

Found on Kangaroo Island, Fleurieu Peninsula and the lower South-east in South Australia, growing in swamps and other damp areas, on sandy soil. Also found in all States. Native. Uncommon in South Australia. Common in the other States.
Herbarium regions: Southern Lofty, Kangaroo Island, South Eastern
NRM regions: Adelaide and Mount Lofty Ranges, Kangaroo Island, South East
AVH map: SA distribution map (external link)

Plant description

Perennial sedge with subterete or somewhat angled or compressed stems to 100 cm high, usually with 1 node above the base. Basal leaves rather wider than the stems, more or less compressed. Stem leaves with long sheaths and short channelled blades, all the blades pungent-pointed. Flowers in narrow, dense or interrupted zig-zag panicle with reddish or brown ovoid spikelets in erect clusters, crowded along the branches. Flowering between spring and summer. Fruits are long, dense golden-brown heads at the tip of stems. Seeds are red- brown ovoid nut to 3 mm long and 2 mm wide with shiny smooth surface. Seed embryo type is capitate.

Seed collection and propagation

Collect seeds between March and December. Collect whole 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. Not all mature-looking seeds are viable. From two collections, the seed viability was average to high, ranging from 65% to 80%. This species is generally difficult to germinate, it has morphophysiological dormancy and complex germination requirements.

Seeds stored:
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LocationNo. of seeds
(weight grams)
Number
of plants
Date
collected
Collection number
Collection location
Date
stored
% ViabilityStorage
temperature
BGA 
MSB
6,600 (18.25 g)
6,600 (18.25 g)
50+5-Apr-2005DJD131
Southern Lofty
28-Mar-200680%-18°C
BGA1,200 (3.3 g)50+5-Apr-2005DJD129
Southern Lofty
28-Mar-200665%-18°C
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.