Ranunculus alismifolius
Ranunculus aquatilis
common water plantain buttercup, kidney-leaf buttercup, plantain-leaf buttercup, water-plantain buttercup
renoncule aquatique, water buttercup, water crowfoot, white water butter cup, white water crowfoot, white water crowsfoot, white western buttercup
slender or fusiform-thickened basally, glabrous.
erect or ascending, not rooting nodally, glabrous or hirsute.
glabrous.
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.
laminate and filiform-dissected; laminate leaf blades reniform, 3-parted, 0.4-1.1 × 0.7-2.3 cm, segments obovate or fan-shaped, shallowly cleft, margins crenate;
filiform-dissected leaves with stipules gradually tapering upward, connate for their whole length.
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 hispid, rarely glabrous;
sepals spreading or reflexed, 2-4 × 1-2 mm, glabrous;
petals 5, 4-7 × 1-5 mm;
style 0.1-0.8 mm.
usually recurved.
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.
hemispheric to ovoid, 2-4 × 2-5 mm;
achenes 1-2 × 0.8-1.4 mm, glabrous or hispid;
beak persistent, filiform, 0.1-1.2 mm.
Ranunculus alismifolius
Ranunculus aquatilis
Varieties 6 (6 in the flora).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Varieties 2 (2 in the flora).
Ranunculus aquatilis is very variable. In the past it has often been treated as three or four species and many varieties. These segregate taxa have been based on the size, petiolation and rigidity of the leaves (now known to be primarily under environmental control), petal size and curvature of the fruiting pedicel (both sometimes variable along single stem), and number of achenes per head and length of achene beak (which vary continuously and are not correlated with one another). Unless reliable characters can be found, only two of the taxa recognized in older floras can be maintained.
(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 |
1. Leaves of 2 types: laminate and filiform-dissected; w North America. | var. aquatilis |
1. Leaves all filiform-dissected; widespread. | var. diffusus |
- 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, Turner Photog. - WildflowerSearch
- iNaturalist (observations)
- USDA Plants Database
- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
