Ranunculus testiculatus |
Ranunculus austro-oreganus |
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bur buttercup, hornseed buttercup, tubercled crowfoot |
southern Oregon buttercup |
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Roots | never tuberous. |
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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. |
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Ranunculus testiculatus |
Ranunculus austro-oreganus |
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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 |
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]
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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 | ||
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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