Northern Prairie Wildlife Research Center
Aquatic and Wetland Vascular Plants of the Northern Great Plains
9. Ranunculaceae, the Buttercup Family
4. Ranunculus L. -- Buttercup, crowfoot
11. Ranunculus subrigidus W.B. Drew -- White water-crowfoot
Very similar to R. longirostris, occasionally stranded on mud in late
summer and assuming a semiterrestrial growth form. Stems usually 2-6
dm long, sometimes over 10 dm long in clear deep water, or only to 1 dm long
when stranded, simple or sparingly branched, rooting at the lower nodes. Leaves
all cauline or some basal on semiterrestrial forms, the blades finely divided
as in R. longirostris, roughly globular in outline, usually 1-3 cm across,
often smaller, the filamentous leaf segments flattened on stranded plants; petioles
consisting of the stipular leaf bases or extending slightly beyond the dilated
base, 2-5 mm long, glabrous or pubescent. Flowers as in R. longirostris.
Achenes 30-45(80) in a globose head 3-5 mm long, 3-5 mm thick; achene
body obovoid, transversely wrinkled, hispidulous on the back, 1-1.5 mm long,
averaging 1.25 mm or less long, the beak 0.2-0.5 mm long (often nearly beakless
when dried); receptacle 1-2 mm long, pubescent; peduncles strongly
recurved in fruit, (1)3-10 cm long. Jun--Aug. Marshes, lakes, ponds, water-filled
ditches and slow-moving streams; common in ND, SD, e MT, WY and perhaps w NE;
(Que. to N.W. Terr. and B.C., s to MA, MI, IA, TX, n Mex. and CA). R. circinatus
Sibth. var. subrigidus (W. B. Drew) Benson; R. aquatilis L.
The white water-crowfoots, R. longirostris and R. subrigidus,
are especially conspicuous in June when the white blossoms may literally cover
the water surface of some marshes.
Ranunculus subrigidus
Previous Species -- Ranunculus sceleratus
L. -- Cursed crowfoot
Return to Family -- Ranunculaceae -
The Buttercup Family
U.S. Department of the Interior |
U.S. Geological Survey