Plants of
South Australia
Roepera marliesiae
Zygophyllaceae
Marlies Square-fruit Twinleaf,
Square-fruit Twinleaf
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Adelaide
Arkaroola
Ceduna
Coober Pedy
Hawker
Innamincka
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Keith
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Botanical art

Kath Alcock painting: 1

Prior names

Zygophyllum marliesiae

Zygophyllum prismatothecum, partly

Common names

Marlies Square-fruit Twinleaf

Square-fruit Twinleaf

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. Marliesiae named after Mrs Marlies Eichler, wife of Hansjoerg Eichler who always shared in his work, but her contribution is largely unsung.

Distribution and status

Endemic to South Australia and is confined to the Lake Eyre region, growing in a wide range of ecological niche including salt pans, samphire flood plains, limestone formations associated with mound springs, gypseous flats and sand hills. Native. Uncommon in South Australia.
Herbarium regions: Lake Eyre, Gairdner-Torrens
AVH map: SA distribution map (external link)

Plant description

Spreading annual herb to 15 cm high. Leaves petiolate, with 2 pairs of leaflets. Leaflets succulent, elliptic, to 8 mm long and 8.5 mm wide, continuous with petiole and not articulated at base, rounded at the apex. Inflorescence solitary at each node with yellow flowers. This species is related to Roepera prismatotheca and can be distinguished predominantly on fruiting characters, it differs by its longer pedicels in flower and fruit, the elliptic rather than rectangular fruits and by the much shorter apical appendages on the fruit (which continuous with the angle of the fruit wall and not constricted at their base as in R. prismatotheca). Flowering between June and November. Fruits are yellow-green rounded-oblong capsule to 11 mm long, with 4-angles and 4-cells, sides continuous into 4 falcate, appendages at apex. Seeds are brown ovoid to 3.5 mm long and 1.8 mm wide. Seed embryo type is spatulate fully developed.

Seed collection and propagation

Collect seeds between August and December. 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
9,600 (21.4 g)
9,600 (21.4 g)
100+22-Sep-2016JRG453
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.
Germination table:
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