Ranunculus macranthus
Ranunculus aquatilis
large buttercup, showy buttercup, smallflower buttercup
renoncule aquatique, water buttercup, water crowfoot, white water butter cup, white water crowfoot, white water crowsfoot, white western buttercup
tuberous.
erect or decumbent, never rooting nodally, hispid, base not bulbous.
glabrous.
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.
ovate in outline, 3-5-foliolate, 3.8-10 × 2.7-9 cm, leaflets 1x-lobed, ultimate segments narrowly elliptic to oblanceolate, margins entire or with few teeth, apex broadly acute to rounded-obtuse.
receptacle hispid;
sepals spreading or weakly reflexed ca. 1 mm above base, 7-10 × 3-5 mm, hispid;
petals 10-22, yellow, 12-22 × 4-9 mm.
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.
globose to cylindric, 8-14 × 8-10 mm;
achenes 2.2-4.2 × 2.8-3.4 mm, glabrous, margin forming narrow rib 0.4-0.6 mm wide;
beak usually persistent, filiform from deltate base, straight, 2-4 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.
= 32.
Ranunculus macranthus
Ranunculus aquatilis
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. 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
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USDA Plants Database- LBJ Wildflower Center
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