Sheep Sorrel, Sour Weed, Red Sorrel
(Rumex acetosella subsp. acetosella)
Synonyms of Rumex acetosella (7) (Updated on 12-11-21 from Plants of the World Online by Kew): Acetosa acetosella (L.) Mill., Acetosella acetosella (L.) Small, Acetosella multifida subsp. vulgaris (Fourr.) Kubát, Acetosella vulgaris (W.D.J.Koch) Fourr., Lapathum acetosella (L.) Scop., Pauladolfia acetosella (L.) Börner, Rumex infestus Salisb.
Synonyms of Rumex acetosella subsp. acetosella (13) (Updated on 12-11-21): Acetosa hastata Moench, Acetosa parva Gilib., Acetosa repens Gray, Acetosa sterilis Mill., Acetosella multifida subsp. tenuifolia (Wallr.) Kubát, Acetosella vulgaris f. integrifolia (Wallr.) Dostál, Acetosella vulgaris subsp. tenuifolia (Wallr.) P.D.Sell, Lapathum arvense Lam., Rumex acetosella var. tenuifolius Wallr., Rumex arvensis Dulac, Rumex falcarius Willd. ex Ledeb., Rumex fascilobus Klokov, Rumex tenuifolius (Wallr.) Á.Löve
Rumex acetosella L. is the correct and accepted scientific name for this species of Rumex. The genus and species were named and described as such by Carl von Linnaeus in the first edition of the first volume of Species Plantarum in 1753.
Infraspecific names of Rumex acetosella (4): *Rumex acetosella subsp. acetosella (autonym), Rumex acetosella subsp. acetoselloides (Balansa) Den Nijs, Rumex acetosella subsp. arenicola Y.Mäkinen ex Elven, and Rumex acetosella subsp. pyrenaicus (Pourr. ex Lapeyr.) Akeroyd. I think only the last one is found in the United States (in New York). *When infraspecific taxon are named, an autonym (“type-specimen”) is automatically generated whose description is closest to the (original) species. I am not sure how the species and the autonym can have different synonyms…
As of 12-11-21 when this page was last updated, Plants of the World Online lists 195 species in the Rumex genus. Rumex is a member of the plant family Polygonaceae with a total of 56 genera. Those numbers could change periodically as updates are made on POWO.
The above distribution map for Rumex acetosella is from Plants of the World Online and includes the species and all the subspecies. Areas in green are where the species is native and purple where it has been introduced. The map on the USDA Plants Database for the United States and Canada is similar.
The species, or autonym, is found throughout North America while only the subspecies Rumex acetosella subsp. pyrenaicus is found in New York.
The map on iNaturalist shows where members have made observations. Anyone can join and it is a great website to confirm and share your observations. The maps on iNaturalist are continually updated as members post new observations.
THERE ARE SEVERAL LINKS AT THE BOTTOM OF THE PAGE FOR FURTHER READING AND TO HELP WITH A BETTER POSITIVE ID.
I found this good-sized colony of Rumex acetosella, or Sheep Sorrel, in the yard while I was mowing in 2020. I am sure it has been here for years but somehow I just paid attention. I didn’t know what it was at first and probably before I just thought it was smartweed because at a glance that’s what it looked like. But, since I’ve been doing a lot more wildflower ID I knew this wasn’t any Persicaria. Besides, in April they are just beginning to come up. I went around most of the colony so I could take photos later and properly make an ID.
Rumex acetosella is a perennial plant that spreads by seed and long creeping rhizomes and is a native of Eurasia and the British Isles.
So, after taking a lot of photos I uploaded the first one on iNaturalist, entered my location, and within seconds I had the ID of this colony. It is just weird this plant is not growing anywhere else on the farm except this one location in the yard.
Stems are upright or ascending and grow up to 18” tall and often branch out at the base. Each branch terminates with an inflorescence. Stems are ridged and hairless (glabrous) with a papery sheath (ocrea) at the nodes. Stems seem to be green at the bottom but reddish at the top and kind of streaked in the middle.
The interesting leaves can be thin to slightly succulent, narrowly ovate, lanceolate-elliptic, lanceolate (lance-shaped), or oblong-obovate, usually with a pair of triangular spreading basal lobes.
The basal leaves are somewhat larger and form a rosette but I need to take a closer look or maybe find plants somewhere I haven’t mowed. I didn’t notice any rosettes of larger leaves on my first observation of this colony BUT after looking at photos on Missouri Plants I think I have noticed them in other places. So many plants look a lot alike in the spring before they start flowering. Since I mowed this colony a few times I could have damaged the basal leaves.
Flowers are born on long inflorescences with several racemes. It is like the entire upper half or more of the plant is an inflorescence. Flowers are staminate (having stamens but no pistols). None of the flowers were open when I took photos. Flowers are dioecious meaning plants produce all male or all female flowers and they are wind-pollinated. You can see in the above photo the leaves have cut by the mower.
The above photo shows the papery sheaths on the stems where leaves and branches emerge. They become nearly translucent and raggy with age. Stems have ridges that seem to be red-tinged in the middle of the plant and more reddish at the top.
The flowers are hairless I think, or mainly so. What appears to be hair in this photo are likely grass clippings.
The above photo is a good example of an “obovate-lanceolate” type of a leaf. Even though the upper leaves are pretty small, you can see they are lance-shaped, broader in the center, taper to a point, and have interesting spreading basal lobed. Information says the basal lobes are triangular. Hmmm… Interesting how you can see a raised vein on each side of the midrib from the upper surface of the leaf otherwise it is very smooth. Even the leaf margins are smooth. This leaf was fairly thick and fleshy for its size.
The underside of the leaf I was photographing shows a very prominent midrib and a few veins going toward the margins. The undersurface appears kind of powdery but I can’t remember the scientific name. Perhaps finely pubescent…
OH, the leaves have long petioles…
Plants produce oxalic acid which gives it a sour flavor and tannins which contribute to its bitterness. It is used in cooking and in salads but should be used in moderation. The species name acetosella means “acid salts”. Handling the plant can also cause dermatitis in some people.
Rumex acetosella is a problem species that grows in a variety of conditions but prefers acidic soil. It can become quite invasive. Information suggests the species contributes to hay fever due to its windborne pollen.
Normally, I allow plants to naturalize in certain areas, but perhaps this one I should think about eradicating. Information suggests it could be a problem and may be hard to get rid of.
I am going to keep my eye out for some larger rosettes and maybe I can find this plant elsewhere on the farm (ALTHOUGH, I am not sure I want to).
I have enjoyed photographing and learning about the many wildflowers growing on the farm and other areas. My farm is in Windsor, Missouri in Pettis County (Henry County is across the street and Benton and Johnson aren’t far away). I have grown over 500 different plants and most have pages listed on the right side of the blog. I am not an expert, botanist, or horticulturalist. I just like growing, photographing, and writing about my experience. I rely on several websites for ID and a horticulturalist I contact if I cannot figure them out. Wildflowers can be somewhat variable from location to location, so sometimes it gets a bit confusing. If you see I have made an error, please let me know so I can correct what I have written.
I hope you found this page useful and be sure to check the links below for more information. They were written by experts and provide much more information. Some sites may not be up-to-date but they are always a work in progress. If you can, I would appreciate it if you would click on the “Like” below and leave a comment. It helps us bloggers stay motivated. You can also send an email to me at firstname.lastname@example.org. I would enjoy hearing from you especially if you notice something is a bit whacky
FOR FURTHER READING:
PLANTS OF THE WORLD ONLINE (GENUS/SPECIES)
INTERNATIONAL PLANT NAMES INDEX (GENUS/SPECIES)
FLORA OF NORTH AMERICA (GENUS/SPECIES)
WORLD FLORA ONLINE (GENUS/SPECIES)
USDA PLANTS DATABASE
PFAF (PLANTS FOR A FUTURE)
EDIBLE WILD FOOD
NOTE: The data (figures, maps, accepted names, etc.) may not match on these websites. It depends on when and how they make updates and when their sources make updates. Some websites have hundreds and even many thousands of species to keep up with. Accepted scientific names change periodically and it can be hard to keep with as well. Some of the links may use a name that is a synonym on other sites. In my opinion, Plants of the World Online by Kew is the most reliable and up-to-date plant database and they make updates on a regular basis. I make updates “at least” once a year and when I write new pages or add new photos but I do get behind. We are all a work in progress. 🙂