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Electronic Flora of South Australia
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Electronic Flora of South Australia species Fact Sheet

Family: Polygonaceae
Emex australis

Citation: Steinh., Annls.Sci. nat. sÚr. 2, 9:195 (1838).

Synonymy: Not Applicable

Common name: Three-cornered jack, spiny emex, double gee, Cape spinach, Jackie, prickly Jack, goat-heads, devil-face.

Glabrous annual with many or few prostrate or ascending stems to 50 cm long, sometimes reddish; leaves petiolate, ovate, truncate or cordate at the base, rarely more than 6 cm long.

Female flowers subsessile; fruiting perianth 7-10 mm wide, with a somewhat cuneate base, the spines spreading or erect-spreading, the inner perianth-segments broadly ovate, with shortly pointed apices, closing over the apex of the fruit.

image of FSA1_Emex_aus.jpg habit and fruit
Image source: fig. 94a in Jessop J.P. & Toelken H.R. (Ed.) 1986. Flora of South Australia (4th edn).

Published illustration: Cunningham et al. (1982) Plants of western New South Wales, p. 229.

Distribution:    All mainland States.   Native to South Africa (where it was first reported in 1685); naturalised in North America; Hawaii; New Zealand.

Conservation status: naturalised

Flowering time: July — Nov.

SA Distribution Map based
on current data relating to
specimens held in the
State Herbarium of South Australia

Biology: May reduce crop productivity by competition and both the spines and the toxic oxalates cause trouble with stock.

Taxonomic notes: First recorded in S.Aust. in 1833.

Author: Not yet available

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