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Ranunculus austro-oreganus

southern Oregon buttercup

sharpleaf buttercup

Roots

never tuberous.

never tuberous, sometimes thick and ± fleshy proximally.

Stems

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

erect, not rooting nodally, hirsute or strigose, base not bulbous.

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.

broadly ovate to cordate or sometimes reniform in outline, deeply 3-divided or occasionally 3-foliolate, 2.2-6 × 2.5-7.7(-10) cm, divisions 1-2x deeply parted or -dissected, ultimate segments linear to broadly linear, margins entire (occasionally a lobe reduced to large tooth), apex acute or rounded-acute.

Flowers

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.

receptacle glabrous;

sepals spreading or variously reflexed, 4-6 × 2-4 mm, appressed-hirsute;

petals 5(-10), yellow, 7-13 × 4-10 mm.

Heads

of achenes 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.

of achenes hemispheric or globose, 5-8 × 6-8(-10) mm;

achenes 2.2-3.4 × 2-3 mm, glabrous, margin forming narrow rib 0.1-0.2 mm wide;

beak persistent, lanceolate, strongly curved, 0.4-1.6 mm.

Ranunculus austro-oreganus

Ranunculus acriformis

Phenology Flowering spring (May).
Habitat Grassy hillsides
Elevation 500 m [1600 ft]
Distribution
from FNA
OR
[WildflowerSearch map]
from FNA
CO; ID; MT; UT; WY
[WildflowerSearch map]
[BONAP county map]
Discussion

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.)

Varieties 3

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

Parent taxa Ranunculaceae > Ranunculus > subg. Ranunculus > sect. Ranunculus 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. 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
R. abortivus, 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. testiculatus, R. trilobus, R. triternatus, R. turneri, R. uncinatus
Subordinate taxa
R. acriformis var. acriformis, R. acriformis var. aestivalis, R. acriformis var. montanensis
Key
1. Sepals spreading, or reflexed from base, pubescence of appressed hairs; Wyoming, Colorado.
var. acriformis
1. Sepals reflexed 1–3 mm above base, pubescence of spreading hairs; Wyoming, Idaho, Montana, Utah.
→ 2
2. Beak of achene 1.2–1.6mm; receptacle hemispheric to spheric; Utah to Idaho and Montana.
var. montanensis
2. Beak of achene 0.4–1mm; receptacle obpyriform to cylindric; Utah.
var. aestivalis
Name authority L. D. Benson: Amer. Midl. Naturalist 52: 341. (1954) A. Gray: Proc. Amer. Acad. Arts 21: 374. (1886)
Source FNA vol. 3. Treatment author: Alan T. Whittemore. FNA vol. 3. Treatment author: Alan T. Whittemore.
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