Plants of
South Australia
Phlegmatospermum richardsii
Brassicaceae
Nullarbor Cress,
Richard's Cress
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Regional Species Conservation Assessments per IBRA subregion.
Least concern
Near threatened
Rare
Vulnerable
Endangered
Critically endangered
Extinct
Data deficient
Adelaide
Arkaroola
Ceduna
Coober Pedy
Hawker
Innamincka
Marla
Marree
Mount Gambier
Oodnadatta
Renmark
Wudinna
Keith
Yunta
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Prior names

Erysimum richardsii

Scambopus richardsii

Sisymbrium richardsii

Blennodia richardsii

Common names

Nullarbor Cress

Richard's Cress

Etymology

Phlegmatospermum from the Greek 'phlegma' meaning inflammation and 'sperma' meaning a seed, referring to the mucous seeds. Richardsii named after Annie Frances Richards (1845-1930), who lived at Fowlers Bay, South Australia and collected plants for Mueller.

Distribution and status

Found on the Nullarbor in South Australia, growing on sandy soil in open moss covered mallee, Also found in Western Australia. Native. Very rare in South Australia. Very rare in Western Australia.
Herbarium regions: Nullarbor, Eyre Peninsula
NRM regions: Alinytjara Wilurara, Eyre Peninsula
AVH map: SA distribution map (external link)

Plant description

Erect annual herbs to 20 cm tall, covered in hairs. Basal leaves obovate, to 7 cm long, dentate to entire. Stem leaves obovate to oblanceolate, to 4 cm long, shallowly lobed or entire. Inflorescence an elongated spike with yellow flowers. Flowering between July and September. Fruits are brown elliptic to ovate pod to 1 cm long, scarcely winged or notched; valves hairy. Seeds are orange reniform seed to 1.5 mm long and 1.2 mm wide, with very fine tubercules. Seed embryo type is bent.

Seed collection and propagation

Collect seeds between September and November. Collect maturing pods, those turning pale brown with hard seeds inside. Be gentle with the pods as they split open easily. Place the pods in a tray and cover with paper to prevent seeds from popping out and leave to dry for a week. Then rub the dried pods gently by hand 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 one collection, the seed viability was high, at 90%.

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
7,100 (5.86 g)
7,100 (5.86 g)
200+15-Sep-2009DJD1525
Nullarbor
1-Jun-201090%+5°C, -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.