''Rumex spinosus'' (

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 al ...

''Emex spinosa''), commonly known as devil's thorn, spiny dock, or lesser jack, is an annual 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 1 ...

. It originates in the warmer parts of the

old world The "Old World" is a term for Afro-Eurasia that originated in Europe , after Europeans became aware of the existence of the Americas. It is used to contrast the continents of Africa, Europe, and Asia, which were previously thought of by th ...

, but now has spread with humans to other places. It is common in disturbed areas, especially in sandy soils. It has shown some weedy behaviour in restricted areas within southern Australia.

Description

The lesser jack tends to grow as a sprawling weed. The leaves are plain in shape, resembling spinach. The flowers of different sexes are clustered separately on the same plant. The plant produces many seeds with a hard, prickly casing. These are produced both in clusters along the branches and at the base of the stem. The root is thick and succulent. At the end of the plant's life, the root dries up and pulls the seeds at the base of the stem into the ground. The spiny, durable seeds make the plant a nuisance around human habitats, much like the similarly shaped seeds of '' Tribulus terrestris''.

Taxonomy

''Rumex spinosus'' was first described by

Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, ...

in 1753. It was transferred to the genus ''Emex'' by Francisco Campderá in 1819. However in 2015, Schuster et al. demoted ''Emex'' to a subgenus of ''Rumex'', restoring the species to Linnaeus's original genus. a move accepted by

Plants of the World Online Plants of the World Online (POWO) is an online database published by the Royal Botanic Gardens, Kew. It was launched in March 2017 with the ultimate aim being "to enable users to access information on all the world's known seed-bearing plants ...

, among other sources.

Uses

Although bitter, the root and leaves can be eaten.

References

spinosus Plants described in 1753 Taxa named by Carl Linnaeus {{Polygonaceae-stub