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Labrador buttercup, prairie buttercup, prairie crowfoot

sagebrush buttercup, smooth buttercup

Roots

slender, 0.8-1.8 mm thick.

cylindric, 1-3 mm thick.

Stems

erect, 5-22 cm, pilose or occasionally glabrous, each with 3-12 flowers.

prostrate or ascending, 4-15 cm, glabrous, each with 1-4 flowers.

Basal leaves

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.

persistent, blades reniform or obovate to very narrowly elliptic, 0.7-5.2 × 1-2 cm, base truncate, obtuse or attenuate, margins entire or with 3 broad, apical crenae, apex rounded to acute.

Flowers

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.

pedicels glabrous or nearly so;

receptacle glabrous;

sepals 5-8 × 3-7 mm, abaxially glabrous or sparsely pilose, hairs colorless;

petals 5-10, 8-13 × 5-12 mm;

nectary scale glabrous or ciliate.

Heads of achenes

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, 7-12(-20) × 6-11(-20) mm;

achenes 1.4-2.2 × 1.1-1.8 mm, usually finely pubescent;

beak subulate or lance-subulate, straight or curved, 0.4-1 mm.

2n

= 16.

Ranunculus rhomboideus

Ranunculus glaberrimus

Phenology Flowering spring (Apr–Jun).
Habitat Prairies, or occasionally open woods or thickets
Elevation 0-900 m (0-3000 ft)
Distribution
from FNA
IA; IL; MI; MN; MT; ND; NE; SD; WI; AB; BC; MB; NT; ON; SK
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CA; CO; ID; MT; ND; NE; NM; NV; OR; SD; UT; WA; WY; AB; BC; SK
[WildflowerSearch map]
[BONAP county map]
Discussion

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.)

Varieties 2 (2 in the flora).

Usually only a minority of the ovaries develop, and the fruiting receptacle is completely hidden by aborted ovaries. Populations growing at high elevations (Ranunculus glaberrimus var. ellipticus) and low elevations (var. glaberrimus) are usually well differentiated, but these varieties intergrade at intermediate elevations.

The Thompson Indians rubbed the flowers or the whole plant of Ranunculus glaberrimus on arrow points as a poison (D. E. Moerman 1986).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Basal leaf blades ovate to obovate, usually shallowly lobed; bracts 3-lobed, lobes equal in size; 400–2000 m.
var. glaberrimus
1. Basal leaf blades elliptic to oblanceolate, usually undivided; bracts 3-lobed, middle lobe much larger; 1200–3600 m.
var. ellipticus
Source FNA vol. 3. FNA vol. 3.
Parent taxa Ranunculaceae > Ranunculus > subg. Ranunculus > sect. Epirotes Ranunculaceae > Ranunculus > subg. Ranunculus > sect. Epirotes
Sibling taxa
R. abortivus, R. acriformis, R. acris, R. adoneus, R. alismifolius, R. allegheniensis, R. allenii, R. ambigens, R. andersonii, R. aquatilis, R. arizonicus, R. arvensis, R. auricomus, R. austro-oreganus, R. bonariensis, R. bulbosus, R. californicus, R. canus, R. cardiophyllus, R. cooleyae, R. cymbalaria, R. eschscholtzii, R. fascicularis, R. fasciculatus, R. ficaria, R. flabellaris, R. flammula, R. gelidus, R. glaberrimus, R. glacialis, R. gmelinii, R. gormanii, R. harveyi, R. hebecarpus, R. hederaceus, R. hispidus, R. hydrocharoides, R. hyperboreus, R. hystriculus, R. inamoenus, R. jovis, R. kamtschaticus, R. lapponicus, R. laxicaulis, R. lobbii, R. macauleyi, R. macounii, R. macranthus, R. marginatus, R. micranthus, R. muricatus, R. nivalis, R. occidentalis, R. oresterus, R. orthorhynchus, R. pacificus, R. pallasii, R. parviflorus, R. pedatifidus, R. pensylvanicus, R. platensis, R. populago, R. pusillus, R. pygmaeus, R. ranunculinus, R. recurvatus, R. repens, R. sabinei, R. sardous, R. sceleratus, R. sulphureus, R. testiculatus, R. trilobus, R. triternatus, R. turneri, R. uncinatus
R. abortivus, R. acriformis, R. acris, R. adoneus, R. alismifolius, R. allegheniensis, R. allenii, R. ambigens, R. andersonii, R. aquatilis, R. arizonicus, R. arvensis, R. auricomus, R. austro-oreganus, R. bonariensis, R. bulbosus, R. californicus, R. canus, R. cardiophyllus, R. cooleyae, R. cymbalaria, R. eschscholtzii, R. fascicularis, R. fasciculatus, R. ficaria, R. flabellaris, R. flammula, R. gelidus, R. glacialis, R. gmelinii, R. gormanii, R. harveyi, R. hebecarpus, R. hederaceus, R. hispidus, R. hydrocharoides, R. hyperboreus, R. hystriculus, R. inamoenus, R. jovis, R. kamtschaticus, R. lapponicus, R. laxicaulis, R. lobbii, R. macauleyi, R. macounii, R. macranthus, R. marginatus, R. micranthus, R. muricatus, R. nivalis, R. occidentalis, R. oresterus, R. orthorhynchus, R. pacificus, R. pallasii, R. parviflorus, R. pedatifidus, R. pensylvanicus, R. platensis, R. populago, R. pusillus, R. pygmaeus, R. ranunculinus, R. recurvatus, R. repens, R. rhomboideus, R. sabinei, R. sardous, R. sceleratus, R. sulphureus, R. testiculatus, R. trilobus, R. triternatus, R. turneri, R. uncinatus
Subordinate taxa
R. glaberrimus var. ellipticus, R. glaberrimus var. glaberrimus
Name authority Goldie: Edinburgh J. Sci. 6: 329. (1822) Hooker: Fl. Bor.-Amer. 1: 12. (1829)
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