Ranunculus alismifolius
Ranunculus acris
common water plantain buttercup, kidney-leaf buttercup, plantain-leaf buttercup, water-plantain buttercup
acrid buttercup, bouton d'or, meadow buttercup, renoncule âcre, tall buttercup, tall crowfoot
slender or fusiform-thickened basally, glabrous.
never tuberous.
erect or ascending, not rooting nodally, glabrous or hirsute.
erect from short caudex or rhizome, never rooting nodally, hispid, strigose, or glabrous, base not bulbous.
basal leaf blades with base acute;
proximal cauline leaf blades lanceolate, ovate, or elliptic, 1.8-14.1 × 0.7-2.9 cm, base acuminate to rounded, margins entire or serrulate, apex obtuse to acuminate.
blades pentagonal in outline, deeply 3-5-parted, 1.8-5.2 × 2.7-9.8 cm, segments 1-2x-lobed or -parted, ultimate segments narrowly elliptic or oblong to lanceolate, margins toothed or lobulate, apex acute to rounded.
bracts lanceolate.
receptacle glabrous;
sepals 5, spreading or reflexed from base, 2-6 × 1-4 mm, glabrous or hirsute;
petals 5-12, 5-14 × 2-8 mm;
nectary scales glabrous.
receptacle glabrous;
sepals spreading, 4-6(-9) × 2-5 mm, hispid;
petals 5, yellow, 8-11(-17) × 7-13 mm.
hemispheric to globose, 3-7 × 4-8 mm;
achenes 1.6-2.8 × 1.2-2 mm, glabrous or rarely hispid;
beak lance-subulate, straight or weakly curved, 0.4-1.2 mm.
globose, 5-7(-10) mm wide;
achenes 2-3 × 1.8-2.4 mm, glabrous, margin forming narrow rib 0.1-0.2 mm wide;
beak persistent, deltate, usually with tip short or long, straight or curved, subulate, 0.2-1 mm.
= 14.
Ranunculus alismifolius
Ranunculus acris
Varieties 6 (6 in the flora).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Ranunculus acris is variable in form and division of leaves, size of achene beak, and form of indument on the proximal stem. Most North American plants are weedy and have poorly differentiated caudices; these forms probably were introduced from Eurasia. Rhizomatous plants with large flowers (parenthetic measurements above) found in the Aleutian Islands of Alaska and in Greenland are probably native. Aleutian populations of this form have been called R. acris var. frigidus Regel or R. grandis Honda var. austrokurilensis (Tatewaki) H. Hara. Both names were originally applied to Asiatic plants, and their applicability to American specimens is open to question.
Some Native American tribes used Ranunculus acris as an analgesic, a dermatological or oral aid, an antidiarrheal, antihermorrhagic, and a sedative (D. E. Moerman 1986).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Petals 7–12 on most flowers, 2–3 mm broad. | var. montanus |
1. Petals 4–6(–8), 2–8 mm broad. | → 2 |
2. Stems 3.5–8 mm thick; leaf margins serrulate. | var. alismifolius |
2. Stems 1–3 mm thick; leaf margins entire. | → 3 |
3. Leaf blades ovate or elliptic. | var. alismellus |
3. Leaf blades broadly to narrowly lanceolate. | → 4 |
4. Petals 10–14 mm; California and Nevada. | var. lemmonii |
4. Petals 5–8 mm; widespread. | → 5 |
5. Roots fusiform-thickened proximally; stems and petioles glabrous or pubescent. | var. davisii |
5. Roots not or scarcely fusiform-thickened proximally; stems and petioles glabrous. | var. hartwegii |
- Local floras:
BC, 
CA, 
OR, 
WA - Local Web sites: CalFlora, CalPhotos,
Flora NW, 
PNW Herbaria, Turner Photog. 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
- Local floras: BC, CA, OR, WA
- Local Web sites: CalFlora, CalPhotos, Flora NW,
Go Botany, 
IL Wildflowers, 
KS Wildflowers, 
MD Biodiversity, 
MI Flora, 
MN Wildflowers, 
MO Plants, PNW Herbaria - WildflowerSearch
- iNaturalist (observations)
- USDA Plants Database
- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
