Ranunculus aquatilis L.
white water-buttercup (white water buttercup; white water crowfoot)
Ranunculaceae (Buttercup family)

Introduction to Vascular Plants

Photograph

© Allan Carson     (Photo ID #17820)


Map

E-Flora BC Static Map

Distribution of Ranunculus aquatilis
Click here to view the full interactive map and legend

Species Information

General:
Aquatic, perennial herb, rooting from nodes of lower stems; stems weak, few-branched, creeping or floating, 20-80 cm long, often mat-forming, smooth.
Leaves:
All alternate stem leaves, of two possible types, the floating leaves usually kidney-shaped, 3-parted, 5-8 mm long, 9-15 mm wide, the leaflets elliptic or egg-shaped, margins often notched, unstalked or the stalks 15-40 mm long, the submerged leaves 3 to 5 times 3-dissected, the segments thread-like, the stalks 1-12 mm long; leaves, stalks and stipule-sheaths usually fine-hairy.
Fruits:
Achenes, 10 to 20 in an egg- to globe-shaped head 2-4 mm long, 2-5 mm wide, the achenes egg-shaped, flattened, 1-2 mm long, 0.8-1.4 mm wide, smooth or stiff-hairy; beaks persistent, thread-like, 0.1-1.2 mm long.
Notes:
The taxonomy of the R. aquatilis complex, at least in North America, remains unclear. The treatment by Whittemore (1997), which we have followed, has included some of our W North American plants with the Eurasian var. aquatilis. The recognition of only two varieties in BC, at least until taxonomic problems are resolved, appears to be the only realistic treatment.

1. Floating leaves simple and dissimilar to the submerged, filiform leaves................. var. aquatilis

1. Floating leaves, if any, similar to the submerged, filiform leaves.................. var. diffusus With.

SourceThe Illustrated Flora of British Columbia

Ecology

Ecological Framework for Ranunculus aquatilis

The table below shows the species-specific information calculated from
original data (BEC database) provided by the BC Ministry of Forests and Range.
(Updated August, 2013)

Site Information
Value / Class

Avg

Min

Max

Elevation (metres)
901 0 1720
Slope Gradient (%)
2 0 42

Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]

90 32 150
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
6 4 8
Modal Nutrient Regime
Class
D
# of field plots
 species was recorded in:
19
Modal BEC Zone Class
IDF

All BEC Zones (# of stations/zone) species was recorded in

BG(1), BWBS(1), CDF(2), CWH(1), ESSF(2), ICH(1), IDF(5), MS(1), PP(1), SBPS(2), SBS(2)

Habitat and Range

Ponds and slow-moving streams in the lowland, steppe and montane zones; var. diffusus - common throughout BC, var. aquatilis - infrequent in S BC east of the Coast-Cascade Mountains; var. diffusus - throughout N.A. north of MX, var. aquatilis - circumpolar, N to AK, YT and NT and S to MT, WY, UT, TX, CA and MX; Eurasia, S America.

SourceThe Illustrated Flora of British Columbia

Synonyms

Synonyms and Alternate Names:
Batrachium aquatile (L.) Dumort.
Batrachium circinatum (Sibth.) Rchb.
Batrachium circinatum subsp. subrigidum (W. Drew) A. Löve & D. Löve
Batrachium longirostre (Godr.) F.W. Schultz
Ranunculus amphibius James
Ranunculus aquatilis var. diffusus With. p.p.
Ranunculus aquatilis var. hispidulus E. Drew
Ranunculus aquatilis var. longirostris (Godr.) G. Lawson
Ranunculus aquatilis var. subrigidus (W. Drew) Breitung
Ranunculus aquatilis var. typicus L.D. Benson
Ranunculus circinatus auct. non Sibth.
Ranunculus circinatus var. subrigidus (W. Drew) L.D. Benson
Ranunculus subrigidus W. Drew
Ranunculus trichophyllus var. hispidulus (E. Drew) W. Drew
Ranunculus usneoides Greene