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Aquatic and Wetland Vascular Plants of the Northern Great Plains

9. Ranunculaceae, the Buttercup Family

4. Ranunculus L. -- Buttercup, crowfoot

7. Ranunculus longirostris Godr. -- White water-crowfoot

Submersed, mostly glabrous perennial. Stems floating, elongate, flexuous, mostly 3-8 dm long, simple or sparingly branched, rooting from the lower nodes. Leaves all cauline, the blades finely divided into filiform segments, once or twice trichotomous, then dichotomous, globular in outline, reniform when flattened, 1-2 cm long, 1.5-3 cm wide; petioles consisting of the inflated stipular leaf bases, 2-4 mm long, glabrous or pubescent. Flowers solitary from the axils in the upper portion of the stem, white; sepals 5(6), purplish-green, spreading, 2-3.5 mm long, deciduous shortly before the petals; petals 5, white, suffused with yellow at the base, 4-9 mm long; stamens 10-20. Achenes (7)15-25, in a hemispheric to globose head 3-5 mm long, 3-6 mm thick; achene body obovoid, transversely ridged, glabrous or slightly hispid, averaging 1.5 mm long, the beak prominent, slender and straight, 0.7-1.1 mm long (often shorter when dried); receptacle 1-2 mm long, pubescent; peduncles recurved in fruit, 1-5 cm long. Jun--Jul, occasionally in Aug--Sep. Slow streams, ponds, marshes and water-filled ditches, usually in calcareous water; occasional in the n part, common s; (Que. to Sask., s to DE, TN, AL, AR, TX, NM, ID and NV). R. aquatilis L., misapplied.
GIF-Ranunculus longirostris
Ranunculus longirostris. R. subrigidus is very similar by has more achenes with shorter beaks.
GIF- Distribution Map

Map key

Previous Species -- Ranunculus hispidus Michx. -- Marsh buttercup
Return to Family -- Ranunculaceae - The Buttercup Family
Next Species -- Ranunculus macounii Britt. -- Macoun's buttercup

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