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bur buttercup, hornseed buttercup, tubercled crowfoot

renoncule soufrée, sulphur buttercup

Roots

slender, 0.4-1 mm thick.

Stems

erect or ascending, not rooting nodally, villous, not bulbous-based.

erect from short caudices, 3-20 cm, sparsely pilose to glabrous, each with 1-3 flowers.

Basal leaves

blades broadly spatulate in outline, 1-2x-dissected, 0.9-3.8 × 0.5-1.5 cm, segments linear, margins entire, apex obtuse to acuminate.

persistent, blades transversely elliptic to orbiculate, 1-3 × 1-3 cm, base obtuse to nearly truncate, margins crenate or else blades shallowly 3-lobed with crenate lateral lobes, apex rounded or rounded-apiculate.

Flowers

receptacle glabrous;

sepals spreading, 3-6 × 1-2 mm, villous;

petals yellow, 3-5 × 1-3 mm.

pedicels sparsely brown-pilose;

receptacle brown-pilose;

sepals 6-8 × 3-6 mm, abaxially densely brown-hispid;

petals 5(-6), 8-12 × 6-10 mm;

nectary scale glabrous.

Heads of achenes

cylindric, 9-16(-27) × 8-10 mm;

achenes 1.6-2 × 1.8-2 mm, tomentose;

beak persistent, lanceolate, 3.5-4.5 mm.

ovoid-cylindric or ovoid, 6-7(-9) × 5-6 mm;

achenes 1.8-2.2 × 1.4-1.8 mm, glabrous or sparsely brown-hispid;

beak slender, straight or curved, 0.8-1.4 mm.

Tuberous

roots absent.

2n

= 42, ca. 80, ca. 84, 96, ca. 98.

Ranunculus testiculatus

Ranunculus sulphureus

Phenology Flowering spring (Apr–May). Flowering late spring–summer (Jun–Sep).
Habitat Disturbed areas, especially in grassland Meadows and seepy slopes, often around late snowbeds, bogs, and streamsides
Elevation 400-2500 m (1300-8200 ft) 0-1100 m (0-3600 ft)
Distribution
from FNA
AZ; CA; CO; IA; ID; KS; MN; MO; MT; ND; NE; NM; NV; OH; OR; SD; UT; WA; WY; BC; SK; native to Eurasia [Introduced in North America]
[WildflowerSearch map]
from FNA
AK; BC; NF; NT; QC; YT; Greenland; Eurasia
[BONAP county map]
Discussion

In North America, Ranunculus testiculatus seems to be expanding its range rapidly in arid and semiarid areas. A second species of this subgenus, R. falcatus Linnaeus [Ceratocephala falcata (Linnaeus) Persoon], has been reported from North America, but all reports seem to be based on misidentified material of R. testiculatus.

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

Material of Ranunculus sulphureus from the Aleutian Islands has 3-lobed leaves similar to those of R. nivalis. These plants are sometimes separated as R. sulphureus var. intercedens.

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

Source FNA vol. 3. FNA vol. 3.
Parent taxa Ranunculaceae > Ranunculus > subg. Ceratocephala 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. rhomboideus, R. sabinei, R. sardous, R. sceleratus, R. sulphureus, 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. 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. rhomboideus, R. sabinei, R. sardous, R. sceleratus, R. testiculatus, R. trilobus, R. triternatus, R. turneri, R. uncinatus
Synonyms Ceratocephalus orthoceras, Ceratocephalus testiculatus R. sulphureus var. intercedens
Name authority Crantz: Stirp. Austr. Fasc. 2: 97. (1763) Solander: in C. J. Phipps, Voy. North Pole, 202. (1774)
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