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bur buttercup, hornseed buttercup, tubercled crowfoot

Mississippi buttercup

Roots

not thickened basally, glabrous.

Stems

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

erect or ascending, often rooting at proximal nodes, glabrous or sparsely pilose.

Basal leaf

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.

Proximal cauline leaf blades

ovate to lanceolate or narrowly elliptic, 1.5-5.7 × 0.4-2.4 cm, base cordate to acute, margins finely denticulate or entire, apex broadly rounded to acuminate.

Inflorescences

bracts linear to lanceolate or oblanceolate.

Flowers

receptacle glabrous;

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

petals yellow, 3-5 × 1-3 mm.

receptacle glabrous;

sepals 4-5, spreading or reflexed from base, 2-3 × 1.5-3 mm, glabrous or pubescent;

petals 4-6, 2-6 × 1-2 mm;

nectary scales 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.

hemispheric to ovoid, 2-4 × 2-3 mm;

achenes 0.8-1 × 0.8 mm, glabrous;

beak deciduous, leaving stump 0.1-0.2 mm.

Tuberous

roots absent.

Ranunculus testiculatus

Ranunculus laxicaulis

Phenology Flowering spring (Apr–May). Flowering late winter–summer (Mar–Jul).
Habitat Disturbed areas, especially in grassland Around ponds and ditches, in meadows, roadsides, and open woods
Elevation 400-2500 m (1300-8200 ft) 0-100 m (0-300 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
AL; AR; DE; GA; IL; IN; KS; KY; LA; MD; MO; MS; NC; NJ; OK; SC; TN; TX; VA
[WildflowerSearch map]
[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.)

Source FNA vol. 3. FNA vol. 3.
Parent taxa Ranunculaceae > Ranunculus > subg. Ceratocephala Ranunculaceae > Ranunculus > subg. Ranunculus > sect. Flammula
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. 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
Synonyms Ceratocephalus orthoceras, Ceratocephalus testiculatus R. mississippiensis, R. subcordatus, R. texensis
Name authority Crantz: Stirp. Austr. Fasc. 2: 97. (1763) Darby: Man. Bot. 2: 4. (1841)
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