''Rumex hypogaeus'' (

synonym A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...

''Emex australis''), commonly known in English as southern threecornerjack, devil's thorn, or double gee (also doublegee, from the old Afrikaner name dubbeltge-doorn - 'double thorned'), is a herbaceous plant of the

Polygonaceae The Polygonaceae are a family of flowering plants known informally as the knotweed family or smartweed—buckwheat family in the United States. The name is based on the genus ''Polygonum'', and was first used by Antoine Laurent de Jussieu in 1789 ...

. It is native in

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countri ...

and is an invasive species in

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

in the USA &

Pakistan Pakistan ( ur, ), officially the Islamic Republic of Pakistan ( ur, , label=none), is a country in South Asia. It is the world's List of countries and dependencies by population, fifth-most populous country, with a population of almost 24 ...

Description

It grows to heights of from 10 to 60 cm and its stems may be prostrate, decumbent, or ascending. The base is often reddish. The leaves are stalked and without any surface covering, with the leaf blade being 1-10 by 0.5–6 cm. There are 1 to 8 flowers with stamens per sheathed bundle and these flowers have narrow oblong tepals which are 1.5–2 mm. The female flowers occur as groups of 1 to 4 per sheathed bundle, and the outer tepals are ovate to oblong and 4–6 mm in fruit, while the inner tepals are broadly triangular and, 5–6 mm in fruit. The achenes (dry 1-seeded fruits not opening at maturity) are 4-6 by 2–3 mm, and shiny. It flowers all year round.

Distribution and habitat

It favours disturbed sites, on sandy soils. It is native to South Africa and has become naturalised in California, Trinidad, Europe, India, Pakistan, Taiwan, Hawaii, and Australia.

Weed

Common names in Australia, where it is a weed, include: bindies, spiny emex, doublegee, double gee, double-gee, three corner jack, three-cornered jack, goat's head burr, goathead, jackie, prickly jack, cape spinach, devil's face, devil's thorn, bullhead, bull head, and cat's head.

Treatment

Small infestations and isolated plants of ''Rumex hypogaeus'' can be dug out. When plants are seeding then they should be destroyed by burning. Control programs work best when all plants are killed shortly after having emergence, and should continue for several years.

Gallery

Emexaustralis.jpg, The fruits, most often almost black in colour Rumex hypogaeus P6130413.jpg

References

External links

Jepson Manual TreatmentDistribution map showing where it is native and where introduced''Rumex hypogaeus'' occurrence data
from

GBIF The Global Biodiversity Information Facility (GBIF) is an international organisation that focuses on making scientific data on biodiversity available via the Internet using web services. The data are provided by many institutions from around the ...

''Emex australis'' Profile, photo gallery, distribution
hypogaeus Plants used in traditional African medicine Plants described in 1838 {{Polygonaceae-stub