Plants of
South Australia
Euphorbia serpens (∗)
Creeping Caustic-weed,
Matted Sandmat
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Distribution by Herbarium region
Coober Pedy
Mount Gambier

Prior names

Chamaesyce dallachyana, partly

Chamaesyce drummondii, partly

Common names

Creeping Caustic-weed

Matted Sandmat


Euphorbia name given to an African species by Juba (46 B.C.-19 or 20 A.D.), King of Mauritania, in honour of his Greek physician, Euphorbus, who had discovered its medical uses. Serpens from Latin for snake; referring to the creeping habit of this plant.

Distribution and status

An introduced species native to North and South America that has been recorded in the Southern Lofty and Eyre Peninsula regions of South Australia. It has been recorded in localities such as a reservoir site, the botanic gardens car park and the urban environs of Port Lincoln. It is a weed of disturbed areas and is found in other mainland states. Introduced to Australia and an uncommon weed in South Australia.
Herbarium regions: Eyre Peninsula, Southern Lofty, Green Adelaide
NRM regions: Adelaide and Mount Lofty Ranges, Eyre Peninsula
AVH map: SA distribution map (external link)

Plant description

A small, hairless, low lying annual or short lived perennial herb to 30 cm diameter with corrosive milky sap, usually red stems and blue green, opposite leaves. Distinguished from similar species by its ability to form adventitious roots at the nodes. Flower-heads small, 1 mm long, single or clustered on a short stalk arising from the leaf axils. Flowers most of the year but mainly during the warmer months following rains. Fruits are small, globular, pale green capsule to 3 mm diameter, 3 celled with 1 seed in each cell. Seeds are white to pale grey-brown, somewhat angular, tetraquetrous seed to 1.5 mm long and 0.75 mm wide, covered by a whitish papery outer layer. Seed embryo type is spatulate.

Seed collection and propagation

Collect seeds between October and May. Collect whole plant with maturing capsules that are turning pale green-brown and starting to split open with visible plump pale seeds. Place the plant in a tray and leave to dry for one to two weeks. Then rub the plant especially the capsules gently by hand to dislodge the seeds. Use a fine sieve to separate the unwanted material. Be very careful as the seeds are very small. The seeds are hard and brown. 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 average, at 75%. Seeds are non-dormant, viable seed should germinate readily.