False Rue Anemone
Synonyms of Enemion biternatum (2) (Updated on 3-7-21): Isopyrum biternatum (Raf.) Torr. & A.Gray, Isopyrum biternatum f. acutilobum Fassett
Enemion biternatum Raf. is the correct and accepted scientific name once again for the False Rue Anemone. The genus and species were named and described as such by Constantine Samuel Rafinesque in Journal de Physique in 1820. It was renamed Isopyrum biternatum by John Torrey and Asa Gray in A Flora of North America in 1840 and is now considered a synonym. I noticed a few websites and databases are still using Isopyrum biternatum. It is difficult for many to keep up with name changes.
Some sites are using the scientific name Enemion biternatum (Torr. & A.Gray) Raf. This is completely incorrect. Enemion biternatum Raf. (1820) was the basionym for Isopyrum biternatum (Raf.) Torr. & A.Gray (1840) not the other way around… I pointed that out to the editor of Kew and he made the correction on Plants of the World Online. The Plant List can’t correct it because they are no longer maintained (since 2013), and World Flora Online uploaded the out-of-date data from The Plant List.
Plants of the World Online lists 6 species in the Enemion genus and 4 in the Isopyrum genus (as of 5-27-20 when I am updating this page). They are members of the plant family Ranunculaceae with a total of 52 genera. Those numbers could change as updates are made.
The above distribution map for Enemion biternatum is from Plants of the World Online. The map on the USDA Plants Database for the United States and Canada is the same. A few states and Ontario, Canada have this species in a few areas and it is listed as endangered or threatened 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.
THERE ARE SEVERAL LINKS AT THE BOTTOM OF THE PAGE FOR FURTHER READING AND TO HELP WITH BETTER POSITIVE ID.
I observed only a few small colonies of Enemion biternatum in the woods along the East Fork Tebo Creek on a friend’s property on April 27, 2020. Its most widely used common name is False Rue Anemone and it is a member of the plant family Ranunculaceae. The plants are fairly short and very easy to pass over when not in flower. Enemion biternatum is a perennial and is considered a spring ephemeral. This means after flowering in very early spring the plants will go dormant after setting seed. This is one of the earlier flowering plants in the woods, blooming before the trees leaf out. Plants then emerge again in the fall and remain evergreen over the winter. Plants may produce small tubers.
This perennial wildflower was formerly best known as Isopyrum biternatum (eye-so-PYE-rum by-TER-nat-um).
Its leaves grow in an alternate fashion, are ternately divided or trifoliate, and glabrous (hairless). The basal leaves have longer petioles (stems) than the upper leaves. Leaflets are broadly lanceolate to ovate, 2-3 lobed or parted, and sometimes have shallow notches at the tips. Information says leaves are 2-3 times compound and 3 parted…
Flowering stems, 4-16″ long, emerge from leaf axils along the stem as well as at the top of the plant. Flowering stems also produce leaves. There are a pair of rounded stipules where the flower stalk and leaf stalk join.
Next spring I hope to take more photos of various features. I was unfamiliar with this species when I made my first observation so I didn’t know about its feature characteristics.
Plants produce 1-4 flowers per flowering stem. At first glance, anyone would think this is a five-petaled flower (some may have six but usually only five). However, the petals are actually petal-like sepals and not petals at all. The flowers produce pollen but no nectar. Flowers have 25 to 50 stamens with yellow anthers. These arise from under the green erect carpels that are 3 to 6 in number, each having a short style.
This species is often confused with Thalictrum thalictroides which is the true Rue Anemone.
Hopefully, I will be able to find these plants again in the spring of 2021. As I am writing this page on May 28, the underbrush and other plants are getting taller making the earlier, smaller species harder to find.
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 email@example.com. I would enjoy hearing from you especially if you notice something is a bit whacky
NOTE: Plants of the World Online is the most up-to-date database. It is very hard for some to keep with name changes these days so you may find a few discrepancies between the websites. Just be patient. Hopefully, someday they will be in harmony. 🙂
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
MISSOURI BOTANICAL GARDEN
KANSAS WILDFLOWERS AND GRASSES
FRIENDS OF THE WILDFLOWER GARDEN
NAME THAT PLANT
NOTE: The figures may not match on these websites. It depends on when and how they make updates and when their sources make updates (and if they update their sources or even read what they say). 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. 🙂