Botanical art
Etymology
Swainsona named after Isaac Swainson (1746-1812), an English scientist and horticulturalist who had a private botanic garden near London. Extrajacens refers to the remote location of the populated areas.
Distribution and status
Found in the northern-east corner of South Australia, growing on clay-loam floodplain . Also found in New South Wales. Native. Rare in South Australia. Rare in New South Wales.
Herbarium regions: Lake Eyre, Eastern
NRM region: South Australian Arid Lands
AVH map: SA distribution map (external link)
Plant description
Erect annual herb to 30cm high with several stems arising from a taproot. Leaves ovate to ovate-elliptic, to 35 cm long with 9-25 leaflets, hairs on the margins on the upper surface, apex recurved with a short point. Inflorescence a spike to 15 cm long with 5-10 purple pea flowers. Flowering in spring and summer. Fruits are bladder or balloon-like pod to 20 mm long turning black or dark brown at maturity. Seeds are orange-yellow, semi-flat reniform seeds to 5mm long. Seed embryo type is bent.
Seed collection and propagation
Collect seeds between September and November. Collect mature pods, those turning brown and contain hard seeds. Mature pods can be found lying on the ground next to the plant. Place the pods in a tray and leave to dry for a week. When dried the pods can 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 90% to 100%. This species has physical dormancy that need to be overcome for the seed to germinate (e.g. nicking or softening the seed coat).
Location | No. of seeds (weight grams) | Number of plants | Date collected | Collection number Collection location | Date stored | % Viability | Storage temperature |
---|---|---|---|---|---|---|---|
BGA MSB | 14,800 (281.81 g) 14,800 (281.81 g) | 100+ | 26-Oct-2007 | MJT152 Lake Eyre | 19-Sep-2008 | 90% | -18°C |
BGA MSB | 21,900 (263.44 g) 15,500 (186.23 g) | 100+ | 26-Sep-2008 | DJD1123 Lake Eyre | 20-Jul-2009 | 100% | -18°C |