Ranunculus aquatilis
Ranunculus hystriculus
renoncule aquatique, water buttercup, water crowfoot, white water butter cup, white water crowfoot, white water crowsfoot, white western buttercup
waterfall false buttercup
glabrous.
erect from short caudices, not rooting nodally, glabrous, not bulbous-based.
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.
basal leaf blades semicircular or reniform in outline, shallowly 5-7-lobed, 1.2-4.6 × 1.8-6.6 cm, ultimate segments semicircular, margins crenate, apex rounded or weakly apiculate;
cauline leaves 0-2, scalelike.
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 glabrous;
sepals spreading, white or pale yellow, 6-13 × 3-6 mm, glabrous;
petals 8-12, greenish, 2-4 × 0.6-1.6 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.
ovoid, 6-7 × 6-8 mm;
achenes 3.8-4.2 × 0.8-1 mm, canescent;
beak persistent, filiform, 1.2-1.4 mm, hooked distally.
roots absent.
Ranunculus aquatilis
Ranunculus hystriculus
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.)
Ranunculus hystriculus is endemic to the west slope of the Sierra Nevada.
(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
