Ranunculus rhomboideus
Ranunculus acris
Labrador buttercup, prairie buttercup, prairie crowfoot
acrid buttercup, bouton d'or, meadow buttercup, renoncule âcre, tall buttercup, tall crowfoot
slender, 0.8-1.8 mm thick.
never tuberous.
erect, 5-22 cm, pilose or occasionally glabrous, each with 3-12 flowers.
erect from short caudex or rhizome, never rooting nodally, hispid, strigose, or glabrous, base not bulbous.
persistent, blades ovate to rhombic, undivided or rarely innermost 3-parted, 1.1-5.3 × 0.9-3.6 cm, base obtuse, margins crenate with 5 crenae, apex rounded.
blades pentagonal in outline, deeply 3-5-parted, 1.8-5.2 × 2.7-9.8 cm, segments 1-2x-lobed or -parted, ultimate segments narrowly elliptic or oblong to lanceolate, margins toothed or lobulate, apex acute to rounded.
pedicels pilose;
receptacle pilose;
sepals 4-6 × 1.5-3 mm, abaxially pilose, hairs colorless;
petals 5, 6-8 × 2-4 mm;
nectary scale glabrous.
receptacle glabrous;
sepals spreading, 4-6(-9) × 2-5 mm, hispid;
petals 5, yellow, 8-11(-17) × 7-13 mm.
depressed-globose, 4-6 × 5-7 mm;
achenes 1.8-2.2 × 1.2-1.8 mm, glabrous;
beak slender, curved, 0.2-0.3 mm.
globose, 5-7(-10) mm wide;
achenes 2-3 × 1.8-2.4 mm, glabrous, margin forming narrow rib 0.1-0.2 mm wide;
beak persistent, deltate, usually with tip short or long, straight or curved, subulate, 0.2-1 mm.
= 16.
= 14.
Ranunculus rhomboideus
Ranunculus acris
In addition to the range given above, L. D. Benson (1948) cited nineteenth-century specimens from Quebec, New York, Massachusetts, and Rhode Island. No modern specimens have been seen from those areas.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Ranunculus acris is variable in form and division of leaves, size of achene beak, and form of indument on the proximal stem. Most North American plants are weedy and have poorly differentiated caudices; these forms probably were introduced from Eurasia. Rhizomatous plants with large flowers (parenthetic measurements above) found in the Aleutian Islands of Alaska and in Greenland are probably native. Aleutian populations of this form have been called R. acris var. frigidus Regel or R. grandis Honda var. austrokurilensis (Tatewaki) H. Hara. Both names were originally applied to Asiatic plants, and their applicability to American specimens is open to question.
Some Native American tribes used Ranunculus acris as an analgesic, a dermatological or oral aid, an antidiarrheal, antihermorrhagic, and a sedative (D. E. Moerman 1986).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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