Plants of
South Australia
Roepera sp. Witjira (D.J.Duval 3445)
Zygophyllaceae
Witjira Twinleaf
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Prior names

Zygophyllum sp. Witjira (DJD3445)

Etymology

Roepera (formally Zygophyllum which is from the Greek 'zygon' meaning pair and 'phyllon' meaning leaf; referring to the pair of leaflets making up each leaf) is named after Johannes August Christian Roeper (1801 -1885), a German botanist and physician. Witjira manual script name referring to the location of the type specimen.

Distribution and status

Endemic to South Australia and currently only known from Witjira National Park, growing in gravelly soils on creekline margins. Native. Rare in South Australia.
Herbarium region: Lake Eyre
NRM region: South Australian Arid Lands
AVH map: SA distribution map (external link)

Plant description

Erect annual herb with green, fleshy Y-shaped leaves with ovate leaflets. Flowers bright yellow, large with 5 petals. Flowering between July to September. Fruits 5-angled capsule to 10 mm long, abruptly truncate at base. Seeds are dark brown to black, wedge-shaped to 4 mm long and 2.5 mm wide, with wrinkled surface. Seed embryo type is spatulate fully developed.

Seed collection and propagation

Collect seeds between September and November. Collect semi-dried and dried capsules by running your hands through the stems of the plant. Mature fruits will come off easily and will have a hard and dark seed inside each segment. Place the capsules in a tray and leave to dry for 1 to 2 weeks, depending on how green the fruit is. Then rub the dried capsules to dislodge the seeds. Use a sieve to remove 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. Seed viability is usually high.

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
2,300 (9.65 g)
2,300 (9.65 g)
100+21-Sep-2016DJD3445
Lake Eyre
1-Nov-2017100%-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.