Ranunculus sardous (Hairy Buttercup)

Ranunculus sardous (Hairy Buttercup) on 5-24-22, #883-14. This photo was taken of a colony in front of the pond bank on my farm in Pettis County, Missouri.

Hairy Buttercup, Hairy Crowfoot

Ranunculus sardous

ra-NUN-ku-lus  sar-DOH-us

Synonyms of Ranunculus sardous (24) (Updated on 5-27-22 from Plants of the World Online: Batrachium intermedium (Poir.) Nyman, Notophilus vulgaris Fourr., Ranunculus aggregatus Capelli, Ranunculus agrarius All., Ranunculus apioides Lojac., Ranunculus dulcis Bubani, Ranunculus hirsutus Curtis, Ranunculus intermedius Poir., Ranunculus laevis Paolucci, Ranunculus lanuginosus Costa, Ranunculus mediterraneus Griseb. ex Schur, Ranunculus palensis Bergeret, Ranunculus pallidior Chaix, Ranunculus pallidus Banks & Sol., Ranunculus parviflorus Gouan, Ranunculus parvulus L., Ranunculus pedunculatus Viv., Ranunculus philonotis Ehrh., Ranunculus pseudobulbosus Schur, Ranunculus pseudohirsutus Schur, Ranunculus pumilus Thuill., Ranunculus subtrifolius Schur, Ranunculus verrucosulus Poir. ex Steud., Ranunculus xatardii Lapeyr.

Ranunculus sardous Crantz is the accepted scientific name for this species of Buttercup. It was named and described as such by Heinrich Johann Nepomuk von Crantz in the second volume of Stirpium Austrianum Fasciculus in 1763.

The genus, Ranunculus L., was named and described by Carl von Linnaeus in the first volume of the first edition of Species Plantarum in 1753.

On 5-27-22 when this page was last updated, Plants of the World Online by Kew lists 1,674 species in the Ranunculus genus. It is a member of the plant family Ranunculaceae with 50 genera. Those numbers could change as updates are made on POWO.

Distribution map of Ranunculus sardous from Plants of the World Online. Facilitated by the Royal Botanic Gardens, Kew. Published on the Internet; http://www.plantsoftheworldonline.org/. Retrieved on May 27, 2022.

The above distribution map for Ranunculus sardous is from Plants of the World Online. Areas in green are where the species is native and purple are where it has been introduced. The map on the USDA Plants Database for North America is a little different and includes a few more states. No map is perfect and this species could definitely have a broader range. 

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.

Ranunculus sardous (Hairy Buttercup) on a friend’s farm on 5-22-22, #882-30.

An interesting thing happened at a friend’s farm. One of his pastures was LOADED with a Ranunculus species I thought was probably Ranunculus hispidus. So, I took my camera with me on May 22 in 2022 to take a few photographs to show how the pasture was covered. Then I proceeded to take photos of the flowers and leaves. I had just finished the page for Ranunculus hispidus but you can never have enough photos. The descriptions were fresh in my mind.

Ranunculus sardous (Hairy Buttercup) on a friend’s farm. The photo shows no petiolules on the lateral leaflets. Photo taken on 5-22-22, #882-36.

While looking at the leaves, I realized something was a bit off… Normally, with Ranunculus hispidus, some of the two lateral leaflets have short petiolules but these plants had none! They were all sessile!

I had been working on identifying several species of Ranunculus on my farm but the colony by the front pond was weird. For some reason, they really didn’t “fit” the descriptions I had read. I kept thinking perhaps R. fascicularis but they normally have tuberous roots and they didn’t. Even iNaturalist suggested R. fascicularis, but really the leaves didn’t even match. So, with the new photos I took, I went to iNaturalist and did the drag and drop thing like I normally do. Hmmm… It suggested Ranunculus sardous, commonly known as the Hairy Buttercup. So, I went to the Missouri Plants website to read, once again, the descriptions for R. sardous. Very similar to R. hispidus except for two major things…

Photo of Ranunculus sardous (Hairy Buttercup) showing the fruit on a friend’s farm on 5-22-22, #882-35.

The Missouri Plants website is awesome with great photos and descriptions, and since I am from Missouri it is my “go-to” website when it comes to reading up on wildflower species. The top photo on the R. hispidus page show plants with leaflets with NO petiolules on the lateral leaflets. The two leaf photos show the same thing but the photo of the pressed leaves does show them. HMMM… It further states at the bottom of the page, “a key character to differentiate this from the similar R. sardous is the long-tapered beaks on the achenes.” On the R. sardous page it states, “the key to differentiating this plant from the very similar R. hispidus is the achenes, which in that species are long-tapered. The achenes of R. sardous are much stubbier.

SO, I zoomed in on the above photo and compared the achenes to the photos of both species on Missouri Plants. HOLY CRAP! I realized the Ranunculus on my friend’s farm was actually R. sardous!

Then, I examined the achenes on the HUGE colony below my pond bank again. Guess what? They are also R. sardous! Mystery solved!!!

Ranunculus sardous (Hairy Buttercup) on 5-24-22. #883-22.

Ranunculus sardous is a perennial wildflower that grows from a fibrous root system (non-tuberous or bulbous). The species is a Eurasian native that has spread to several other countries and several states in the United States and western Canada. The Missouri Plants website says when Steyermark’s Flora of Missouri was first published in 1963, only a single specimen was found in St. Louis County. Since then it has spread rampantly in its favored habitats in pastures, fields, pond margins, and low areas… They grow aggressively in the spring when there is plenty of moisture and bloom from April into June or even longer (depending on the weather. Plants can grow around 20” tall in ideal conditions.

Ranunculus sardous (Hairy Buttercup) on 4-28-20, #693-6.

A rosette of multiple basal leaves and stems grows from a short caudex.

Ranunculus sardous (Hairy Buttercup) on 5-24-22, #883-16.

The stems have LOTS of spreading white hairs. The stems can be either green…

Ranunculus sardous (Hairy Buttercup) on 4-29-20, #694-9.

… or reddish color.

Ranunculus sardous (Hairy Buttercup) on 5-24-22, #883-17.

Both the basal and primary leaves are said to be ovate or heart-shaped (cordate) in outline. Each leaflet is 3-lobed. The terminal leaflets of the basal leaves are attached at the of a long petiole while the smaller lateral leaves are “usually” sessile (no petiolules). The lateral leaflets of the similar Ranunculus hispidus “usually” have short petiolules. The petioles and lower leaf undersides are pubescent (hairy) while the upper surface is primarily glabrous (not hairy).

Ranunculus sardous (Hairy Buttercup) on 4-29-20, #694-7.

The primary leaves along the stems grow in an alternate pattern and have shorter petioles.

Ranunculus sardous (Hairy Buttercup) on 5-24-22, #883-18.

The upper leaves become deeply 3-parted with sharply pointed segments and are linear to narrowly oblong-oblanceolate in shape. They have no petioles.

Ranunculus sardous (Hairy Buttercup) on 5-24-22, #883-15.

Flowers have 5 glossy yellow petals with numerous stamens and pistols.

Ranunculus sardous (Hairy Buttercup) on 4-28-20, #693-3.

Ranunculus sardous has 5 reflexed sepals with a well-defined transverse fold.

Ranunculus sardous (Hairy Buttercup) on 5-24-22, #883-20.

The fruit… A cluster of “achenes”, which are the fruit containing the seed. The achenes of R. sardous are keeled along the margin, narrowly winged with short “beaks”. This is an important feature to distinguish this species from R. hispidus which have long-tapered “beaks.”

All Ranunculus species (Buttercup) are poisonous. They have kind of a bitter taste and can cause blistering of the mouth, so livestock generally avoid them. But, in overgrazed pastures, they may if they have no choice. Bloody diarrhea, excessive salivation, colic, blistering of the mouth, mucus membranes, and gastrointestinal tract are symptoms of poisoning. Handling of Ranunculus species can cause contact dermatitis in humans when plants are handled excessively.

I have enjoyed photographing and learning about the many wildflowers growing on the farm and in 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 identified over 200 species of wildflowers (most have pages listed on the right side of the page). 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 few horticulturalists 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 thebelmontrooster@yahoo.com. 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)
TROPICOS (GENUS/SPECIES)
FLORA OF NORTH AMERICA (GENUS/SPECIES)
WORLD FLORA ONLINE (GENUS/SPECIES)
WIKIPEDIA (GENUS/SPECIES)
USDA PLANTS DATABASE
MISSOURI PLANTS
MSU-MIDWEST WEEDS AND WILDFLOWERS
iNATURALIST
WILDFLOWER SEARCH
NORTH CAROLINA STATE UNIVERSITY
GO BOTANY
LOYOLA UNIVERSITY
MARYLAND BIODIVERSITY PROJECT
UNIVERSITY OF WASHINGTON-BURKE HERBARIUM
OWLCATION: BUTTERCUPS AND DAISIES

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. 🙂