Ranunculus aquatilis |
Ranunculus austro-oreganus |
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renoncule aquatique, water buttercup, water crowfoot, white water butter cup, white water crowfoot, white water crowsfoot, white western buttercup |
southern Oregon buttercup |
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Roots | never tuberous. |
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Stems | glabrous. |
erect or ascending, never rooting nodally, crisped-pilose, base not bulbous. |
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Leaves | laminate and filiform-dissected; laminate leaf blades reniform, 3-parted, 0.4-1.1 × 0.7-2.3 cm, segments obovate or fan-shaped, shallowly cleft, margins crenate; filiform-dissected leaves with stipules gradually tapering upward, connate for their whole length. |
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Basal leaf | 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. |
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Flowers | receptacle hispid, rarely glabrous; sepals spreading or reflexed, 2-4 × 1-2 mm, glabrous; petals 5, 4-7 × 1-5 mm; style 0.1-0.8 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. |
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Fruiting pedicels | usually recurved. |
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Heads of achenes | hemispheric to ovoid, 2-4 × 2-5 mm; achenes 1-2 × 0.8-1.4 mm, glabrous or hispid; beak persistent, filiform, 0.1-1.2 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. |
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Ranunculus aquatilis |
Ranunculus austro-oreganus |
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Phenology | Flowering spring (May). | |||||
Habitat | Grassy hillsides | |||||
Elevation | 500 m (1600 ft) | |||||
Distribution |
AK; AL; AR; AZ; CA; CO; CT; DE; IA; ID; IL; IN; KS; KY; MA; MD; ME; MI; MN; MO; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NF; NS; NT; ON; PE; QC; SK; YT; Eurasia
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OR |
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Discussion | Varieties 2 (2 in the flora). Ranunculus aquatilis is very variable. In the past it has often been treated as three or four species and many varieties. These segregate taxa have been based on the size, petiolation and rigidity of the leaves (now known to be primarily under environmental control), petal size and curvature of the fruiting pedicel (both sometimes variable along single stem), and number of achenes per head and length of achene beak (which vary continuously and are not correlated with one another). Unless reliable characters can be found, only two of the taxa recognized in older floras can be maintained. (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.) |
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Key |
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Source | FNA vol. 3. | FNA vol. 3. | ||||
Parent taxa | Ranunculaceae > Ranunculus > subg. Batrachium | Ranunculaceae > Ranunculus > subg. Ranunculus > sect. Ranunculus | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Batrachium aquatile | |||||
Name authority | Linnaeus: Sp. Pl. 1: 556. (1753) | L. D. Benson: Amer. Midl. Naturalist 52: 341. (1954) | ||||
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