Emex australis
| Emex australis | |
|---|---|
 | |
| seeds | |
| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Eudicots |
| (unranked): | Core eudicots |
| Order: | Caryophyllales |
| Family: | Polygonaceae |
| Genus: | Emex |
| Species: | E. australis |
| Binomial name | |
| Emex australis Steinh. | |
Emex australis, commonly known in English as devil's thorn or doublegee (also double gee, from the old Afrikaner name Dubbeltge-Doorn - 'Devil's Thorn'), or three-cornered jack, is a herbaceous plant of the Polygonaceae. It occurs indigenously in South Africa and is also an invasive species in Australia.