Aquatic and Wetland Vascular Plants of the Northern Great Plains
9. Ranunculaceae, the Buttercup Family
4. Ranunculus L. -- Buttercup, crowfoot11. 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
