Ranunculus aquatilis
Ranunculus pensylvanicus
renoncule aquatique, water buttercup, water crowfoot, white water butter cup, white water crowfoot, white water crowsfoot, white western buttercup
bristly buttercup, bristly crowfoot, Pennsylvania buttercup, renoncule de pennsylvanie
never tuberous.
glabrous.
erect, never rooting nodally, hispid, base not bulbous.
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.
blades broadly cordate in outline, 3-foliolate, 1.6-7 × 3-9 cm, leaflets cleft, usually deeply so, ultimate segments narrowly elliptic, margins toothed, apex acute.
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.
receptacle hirsute;
sepals reflexed ca. 1 mm above base, 3-5 × 1.5-2 mm, ± hispid;
petals 5, yellow, 2-4 × 1-2.5 mm.
usually recurved.
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.
cylindric, 9-12 × 5-7 mm;
achenes 1.8-2.8 × 1.6-2 mm, glabrous, margin forming narrow rib 0.1-0.2 mm wide;
beak persistent, broadly lanceolate or nearly deltate, straight or nearly so, 0.6-0.8 mm.
= 16.
Ranunculus aquatilis
Ranunculus pensylvanicus
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.)
Ojibwa tribes used Ranunculus pensylvanicus as a hunting medicine; the Potawatomi used it as an astringent for miscellaneous diseases (D. E. Moerman 1986).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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, 
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
- Local floras: BC, WA
- Local Web sites: Flora NW, Go Botany, IL Wildflowers, MD Biodiversity, MI Flora, MN Wildflowers, PNW Herbaria
- WildflowerSearch
- iNaturalist (observations)
- USDA Plants Database
- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
