{{Short description|Species of flowering plant}} {{For|the rue-anemone|Thalictrum thalictroides}} {{Speciesbox |image=Enemion biternatum Arkansas.jpg |status=G5 |status_system=TNC |status_ref=<ref>{{cite web|url=https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.150438/Enemion_biternatum|title=''Enemion biternatum''|website=NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer|publisher=NatureServe|author=NatureServe|location=Arlington, Virginia|date=5 January 2024|access-date=14 January 2024}}</ref> |genus=Enemion |species=biternatum |authority=Raf. |synonyms=* ''Isopyrum biternatum'' <small>(Rafinesque) Torrey & A. Gray</small> }}
'''''Enemion biternatum''''' (syn. ''Isopyrum biternatum''), commonly known as the '''false rue-anemone''', is a spring ephemeral native to moist deciduous woodland in the eastern United States and extreme southern Ontario.<!-- for range --><ref name="flora">{{EFloras |first=Bruce A. |last=Ford |1 |220004741 |Enemion biternatum |family=Ranunculaceae |accessdate=28 April 2016 }}</ref>
==Description== ''Enemion biternatum'' is a perennial herb.<ref name=":0">{{Cite web |title=Lady Bird Johnson Wildflower Center - The University of Texas at Austin |url=https://www.wildflower.org/plants/result.php?id_plant=ENBI |access-date=2024-03-02 |website=www.wildflower.org}}</ref> The plant sends up evergreen basal leaves in the fall,<ref name="michigan">{{cite web |url=http://michiganflora.net/species.aspx?id=2373 |title=Enemion biternatum |website=Michigan Flora Online |author=A. A. Reznicek |author2=E. G. Voss |author3=B. S. Walters |date=February 2011 |publisher=University of Michigan |accessdate=April 29, 2016}}</ref> and flower stems in the spring. It goes dormant in late spring and early summer after the seed ripens.
Leaves are twice or thrice compound with groups of three leaflets. Leaflets are smooth-edged, irregularly and deeply lobed twice or thrice, often with one to three secondary shallow lobes. Basal leaves are held on long stalks, and there are leaves arranged alternately up the flowering stems, with shorter stalks. All stems are reddish and hairless.<ref name="minnesota">{{Minnesota Wildflowers|Enemion biternatum (False Rue Anemone)|flower|false-rue-anemone}}</ref>
The root system is weakly rhizomatous<ref name="flora" /> and occasionally produces small tubers. Plants spread over time to form thick colonies.<ref name="illinois">{{Illinois Wildflowers|woodland/plants/fs_anemone|False Rue Anemone (Enemion biternatum)}}</ref>
The flowering stems are {{convert|4|to|16|in|cm|-1}} high.<ref name="minnesota" /> Flowers are produced singly or in leafy racemes of two to four flowers,<ref name="eloise">{{cite web |title=False Rue-anemone, Enemion biternatum Raf. |url=http://www.friendsofthewildflowergarden.org/pages/plants/falserueanemone.html |first=G. D. |last=Bebeau |date=2013 |website=Plants of the Eloise Butler Wildflower Garden}}</ref> which means that there are leaves arranged alternately up the stems and flowers are in stems that come out of leaf axils. On either side of the leaf axils are two rounded stipules.<ref name="eloise" />
The flowers have five white petal-like sepals that are each {{convert|5.5|-|13.5|mm|frac=16|abbr=on}} long and {{convert|3.5|-|8.5|mm|frac=16|abbr=on}} wide,<ref name="flora" /> 25-50 stamens with yellow pollen on the anthers, and three to six green carpels.<ref>{{cite book |title=A Flora of North America, Volume 1 |page=660 |date=1838 |first1=John |last1=Torrey |first2=Asa |last2=Gray |url=https://books.google.com/books?id=MUcAAAAAQAAJ&pg=PA660 |publisher=Wiley & Putnam|location=New York}}</ref> If a carpel is fertilized, it develops into a beaked pod (follicle). When ripe, the pod splits open on one side to release several reddish-brown seeds.<ref name="eloise" />
Its habitats include floodplain woods, limestone ledges and rich or calcareous woods or thickets.<ref name=":0" />
<gallery mode=packed> False rue-anemone closeup.jpg|Closeup of a flower Biternate leaves Enemion biternatum.png|Twice three-parted ("biternate") leaf False Rue Anemone (13945647677).jpg|Carpet across the woodland floor </gallery>
===Similar species=== The false rue-anemone is often confused with the similar species, the rue-anemone (''Thalictrum thalictroides''). Both plants have white flowers that appear in early spring and grow in wooded areas. However, the false rue-anemone is more likely to be found in moist bottomlands and can form large colonies, while the rue-anemone grows singly on wooded slopes. Sometimes rue-anemone sepals are pale to dark pink, whereas false rue-anemone sepals are always white. The false rue-anemone holds its flowers in leaf axils, most often singly. In contrast, the flowers of a rue-anemone appear in a cluster above a whorl of leaf-like bracts, most often in groups of three to six. While false rue-anemones always have five sepals, rue-anemones can have five to ten sepals.<ref>{{cite book |last1=Dennison |first1=Edgar |title=Missouri Wildflowers |date=2017 |publisher=Conservation Commission of the State of Missouri |isbn=978-1-887247-59-7 |pages=8–9 |edition=Sixth}}</ref> False rue-anemones have a small cluster of no more than six green carpels in the center of the flower, while rue-anemones sometimes have as many as fifteen. False rue-anemones usually have deep clefts in their leaflets, while rue-anemones do not.<ref>{{cite web |title=Confusing rues: identifying false rue anemone and rue anemone |url=https://illinoisplants.org/confusing-rues-identifying-false-rue-anemone-and-rue-anemone/ |website=Illinois Native Plant Society |date=9 May 2021}}</ref>
==Ecology== The flowers produce pollen but no nectar. Small insects such as sweat bees (''Lasioglossum'' and ''Halictus''), mining bees (''Andrena''), honeybees (''Apis mellifera''), and hoverflies visit the flowers to collect or feed on pollen. Some bees likely visit searching in vain for nectar.<ref name="illinois" />
==Conservation== ''Enemion biternatum'' is listed as a schedule 1 threatened species in Canada, where only six populations were reported in southwestern Ontario.<ref>{{cite web |url=http://www.sararegistry.gc.ca/species/speciesDetails_e.cfm?sid=249 |title=Species Profile (False Rue-anemone) |work=Species at Risk Public Registry |publisher=Government of Canada |date=2005}}</ref> It is listed as an endangered species in Florida, where it has only been reported in Jackson and Washington counties.<ref>{{cite book |last1=Coile |first1=Nancy C. |first2=Mark A. |last2=Garland |date=2003 |title=Notes on Florida's Endangered and Threatened Plants. Botany Contribution No. 38 |url=http://www.virtualherbarium.org/EPAC/Notes2003.pdf |edition= 4th |publisher=Florida Department of Agriculture and Consumer Services, Division of Plant Industry |place=Gainesville |page=29}}</ref>
==References== {{Reflist}}
==External links== {{Commons category}} * {{NPIN |link=1}} * {{Missouri Plants |color=White |leaf=alt |genus=Isopyrum |species=biternatum |link=1}}
{{Taxonbar|from=Q5376756}} {{Authority control}}
biternatum Category:Ephemeral plants Category:Flora of Northern America Category:Taxa named by Constantine Samuel Rafinesque