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bur buttercup, hornseed buttercup, tubercled crowfoot

Ranunculus austro-oreganus

southern Oregon buttercup

Roots

never tuberous.

Stems

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

erect or ascending, never rooting nodally, crisped-pilose, base not bulbous.

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.

blades broadly rhombic to semicircular in outline, 3-parted, 2.8-4.3 × 3-5.5 cm, segments 3-lobed, ultimate segments lanceolate, margins entire or toothed, apex narrowly acute or acuminate.

Flowers

receptacle glabrous;

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

petals yellow, 3-5 × 1-3 mm.

receptacle glabrous;

sepals reflexed 1 mm above base, 4-6 × 1.5-3 mm, densely pilose;

petals 5, abaxially red, adaxially yellow, 10-12 × 4-6 mm.

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, 4-7 × 7-10 mm;

achenes 3.4-4.2 × 2.8-3.2 mm, sometimes basally pilose, margin forming narrow rib 0.1-0.2 mm wide;

beak persistent, lance-subulate, straight or somewhat curved distally, 1.6-2.6 mm.

Tuberous

roots absent.

Ranunculus testiculatus

Ranunculus austro-oreganus

Phenology Flowering spring (Apr–May). Flowering spring (May).
Habitat Disturbed areas, especially in grassland Grassy hillsides
Elevation 400-2500 m (1300-8200 ft) 500 m (1600 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
OR
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.)

Of conservation concern.

Ranunculus austro-oreganus is doubtfully distinct from R. occidentalis var. howellii. L. D. Benson (1954) described the stem as bulbous-based and similar to that of R. bulbosus, but a differentiated base is not evident in material I have seen (some of which was cited by Benson).

(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. Ranunculus
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. 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. testiculatus, R. trilobus, R. triternatus, R. turneri, R. uncinatus
Synonyms Ceratocephalus orthoceras, Ceratocephalus testiculatus
Name authority Crantz: Stirp. Austr. Fasc. 2: 97. (1763) L. D. Benson: Amer. Midl. Naturalist 52: 341. (1954)
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