Plants of
South Australia
Swainsona oroboides
Leguminosae
Kneed Darling Pea,
Variable Swainson-pea
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Adelaide
Arkaroola
Ceduna
Coober Pedy
Hawker
Innamincka
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Keith
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Botanical art

Kath Alcock paintings: 2

Common names

Kneed Darling Pea

Variable Swainson-pea

Etymology

Swainsona named after Isaac Swainson (1746-1812), an English scientist and horticulturalist who had a private botanic garden near London. Oroboides meaning resemble to the genus Orobus, an old genus of Fabaceae family which is now divided into a number of genera; referring to the appearance of the species to a kind of vetch.

Distribution and status

Found mostly in red sand or loam, occasionally in clay in areas with subsoil moisture such as flood-plains or gibber-plains in the north and north-eastern part of South Australia. Also found in Western Australia, Northern territory, Queensland and New South Wales. Native. Common in South Australia. Common in other states.
Herbarium regions: North Western, Lake Eyre, Gairdner-Torrens, Eyre Peninsula
NRM regions: Alinytjara Wilurara, Eyre Peninsula, South Australian Arid Lands
AVH map: SA distribution map (external link)

Plant description

A prostrate or ascending perennial plant with many hairy stems arising from a taproot. Leaves 2-7cm long with 3-7 hairy, narrow lanceolate leaflets. Flowers large, purple and usually on a dense head. Fruits are dark brown, oblong or almost spherical pods 8-14mm long covered in dense hairs. Seeds are orange to brown, semi-flat reniform seeds to 2mm long with a wrinkled surface. Seed embryo type is bent.

Seed collection and propagation

Collect seeds between September and November. Collect mature pods, dark brown containing hard seed. Mature pods can be found lying on the ground next to the plant containing hard seeds. When dried the pods become hard and difficult to open. Use a rubber bung to rub the pods or break the pods open with your fingers to dislodge the seeds. Use a sieve to separate the 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. From two collections, the seed viability were high, ranging from 85% to 95%. This species has physical dormancy that needs to be overcome for the seed to germinate (e.g. nicking or softening the seed coat).

Seeds stored:
  Hide
LocationNo. of seeds
(weight grams)
Number
of plants
Date
collected
Collection number
Collection location
Date
stored
% ViabilityStorage
temperature
BGA6,000 (11.9 g)50+2-Nov-2010MJT331
Lake Eyre
1-Jan-201295%-18°C
BGA860 (1.72 g)20+5-Oct-2010DJD1875
Lake Eyre
1-Jan-201285%-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.