Rumex hypogaeus

{{Speciesbox

|image = Emex australis - Flickr - Kevin Thiele.jpg

|image2 =

|image_caption =

|taxon = Rumex hypogaeus

|authority = T.M.Schust. & Reveal

|synonyms =Emex australis Steinh.

Vibo australis (Steinh.) Greene

|synonyms_ref =

}}

Rumex hypogaeus (synonym Emex australis), commonly known in English as southern threecornerjack,{{PLANTS|id=EMAU|taxon=Emex australis|accessdate=18 January 2016}} devil's thorn,{{citation needed|date=January 2016}} or double gee{{BSBI 2007 |access-date=2014-10-17 }} (also doublegee, from the old Afrikaner name dubbeltge-doorn - 'double thorned'), is a herbaceous plant of the Polygonaceae. It is native in South Africa and is an invasive species in Australia, Texas in the USA, and Pakistan.

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.{{Cite web|title=Emex australis in Flora of North America @ efloras.org|url=http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=242100050|access-date=2020-07-06|website=www.efloras.org}}

It flowers all year round.

Distribution and habitat

It favours disturbed sites, on sandy soils. It is native to South Africa{{Cite web|title=Rumex hypogaeus T.M.Schust. & Reveal {{!}} Plants of the World Online {{!}} Kew Science|url=http://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:77152626-1|access-date=2020-07-06|website=Plants of the World Online}} 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: 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.{{Cite web|title=Weeds Australia Profile: Emex australis|url=https://profiles.ala.org.au/opus/weeds-australia/profile/Emex%20australis|access-date=2020-07-11|website=profiles.ala.org.au}}

= 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 emergence, and should continue for several years.{{Cite book|last=Parsons, W.T & Cuthbertson, E.G.|title=Noxious weeds of Australia|publisher=CSIRO Publishing|year=2001|location=Victoria}}

Gallery

Emexaustralis.jpg|The fruits, most often almost black in colour

Rumex hypogaeus P6130413.jpg

References

External links

[http://ucjeps.berkeley.edu/cgi-bin/get_JM_treatment.pl?5936,5991,5992 Jepson Manual Treatment]
[https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:77152626-1 Distribution map showing where it is native and where introduced]
[https://www.gbif.org/species/8909872 Rumex hypogaeus occurrence data] from GBIF
[https://profiles.ala.org.au/opus/weeds-australia/profile/Emex%20australis Emex australis Profile, photo gallery, distribution]

hypogaeus

Category:Plants used in traditional African medicine

Category:Plants described in 1838