Thedocks andsorrels,genusRumex, are a genus of about 200 species ofannual,biennial, andperennialherbs in thebuckwheat family,Polygonaceae.Members of this genus are very common perennial herbs with a native almost worldwide distribution, and introduced species growing in the few places where the genus is not native.[1]
Some are nuisanceweeds (and are sometimes called dockweed or dock weed), but some are grown for their edibleleaves.[2]Rumex species are used as food plants by thelarvae of a number ofLepidoptera species, and are the only host plants ofLycaena dispar andLycaena rubidus.[3]
They are erect plants, usually with longtaproots. The fleshy to leathery leaves form a basal rosette at the root. The basal leaves may be different from those near theinflorescence. They may or may not havestipules. Minor leaf veins occur. The leaf blade margins are entire or crenate.
The usually inconspicuousflowers are carried above the leaves in clusters. The fertile flowers are mostlyhermaphrodites, or they may be functionally male or female. The flowers and seeds grow on long clusters at the top of a stalk emerging from the basal rosette; in many species, the flowers are green, but in some (such as sheep's sorrel,Rumex acetosella) the flowers and their stems may be brick-red. Each seed is a three-sided achene, often with a round tubercle on one or all three sides.
The genus was first described byCarl Linnaeus in 1753. Within the family Polygonaceae, it is placed in the subfamilyPolygonoideae. The genusEmex was separated fromRumex by Francisco Campderá in 1819 on the basis that it was polygamous (i.e. had both bisexual and unisexual flowers on the same plant). However, some species ofRumex subg.Acetosa also have this characteristic, and most other features that are supposed to distinguishEmex are found in species ofRumex. Accordingly, in 2015, Schuster et al. demotedEmex to a subgenus ofRumex.[4]
Within the subfamily Polygonoideae,Rumex is placed in the tribe Rumiceae, along with the two generaOxyria andRheum. It is most closely related toRheum, which includesRhubarb.[4]
These plants have many uses. Broad-leaved dock (Rumex obtusifolius) used to be called butter dock because its large leaves were used to wrap and conservebutter.
Rumex hymenosepalus has been cultivated in the Southwestern US as a source oftannin (roots contain up to 25%), for use in leather tanning, while leaves and stems are used for amordant-free mustard-coloreddye.
These plants are edible. The leaves of most species containoxalic acid and tannin, and many haveastringent and slightlypurgative qualities. Some species with particularly high levels of oxalic acid are called sorrels (including sheep's sorrelRumex acetosella, common sorrelRumex acetosa, and French sorrelRumex scutatus), and some of these are grown asleaf vegetables or gardenherbs for their acidic taste.[5][6]
In the United Kingdom,Rumex obtusifolius is often found growing nearstinging nettles, owing to both species favouring a similar environment, and there is a widely held belief that the underside of the dock leaf, squeezed to extract a little juice, can be rubbed on the skin to counteract the itching caused by brushing against a nettle plant.[7] Thishome remedy is not supported by any science, although it is possible that the act of rubbing may act as a distractingcounterstimulation, or that belief in the dock's effect may provide aplacebo effect.[8]
In traditional Austrian medicine,R. alpinusleaves and roots have been used internally for treatment of viral infections.[9]
Rumex nepalensis is also has a variety of medicinal uses in the Greater Himalayas, includingSikkim in NortheasternIndia.[10]
^abSchuster, Tanja M.; Reveal, James L.; Bayly, Michael J. & Kron, Kathleen A. (2015). "An updated molecular phylogeny of Polygonoideae (Polygonaceae): Relationships ofOxygonum,Pteroxygonum, andRumex, and a new circumscription ofKoenigia".Taxon.64 (6):1188–1208.doi:10.12705/646.5.
^Friis, Else Marie (1985). "Angiosperm Fruits and Seeds from the Middle Miocene of Jutland (Denmark)".The Royal Danish Academy of Sciences and Letters.24 (3).
^Macroscopic plant remains from the freshwater Miocene of the Nowy Sącz Basin (West Carpathians, Poland) by Maria Łańcucka-Środoniowa, Acta Palaeobotanica 1979 20 (1): 3-117.
