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Ranunculus austro-oreganus

southern Oregon buttercup

Eschscholtz's buttercup, snow buttercup, subalpine buttercup

Roots

never tuberous.

slender, 0.4-1.6 mm thick.

Stems

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

erect or decumbent from short or long caudices, 4-27 cm, glabrous, each with 1-3 flowers.

Basal leaves

persistent, blades reniform or cordate to obovate or broadly oblong, lobed or 3-parted, 0.5-4.1 × 0.8-3.7 cm, segments again 1(-2)×-lobed, base obtuse to cordate, apices of segments rounded in outline.

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.

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.

pedicels glabrous;

receptacle glabrous or sparsely pilose;

sepals 4-8 × 2-6 mm, abaxially glabrous or pilose;

petals 5-8, 6-16 × 4-16 mm;

nectary scale glabrous.

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 cylindric or ovoid, 5-10 × 4-7 mm;

achenes 1.4-2 × 1-1.6 mm, glabrous or sparsely pubescent;

beak lanceolate or subulate, straight (sometimes curved when immature), 0.6-1.8 mm.

Ranunculus austro-oreganus

Ranunculus eschscholtzii

Phenology Flowering spring (May).
Habitat Grassy hillsides
Elevation 500 m [1600 ft]
Distribution
from FNA
OR
[WildflowerSearch map]
from FNA
AK; AZ; CA; CO; ID; MT; NM; NV; OR; UT; WA; WY; AB; BC; NT; YT
[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 6 (5 in the flora).

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

Parent taxa Ranunculaceae > Ranunculus > subg. Ranunculus > sect. Ranunculus Ranunculaceae > Ranunculus > subg. Ranunculus > sect. Epirotes
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. 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. 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. eschscholtzii var. eschscholtzii, R. eschscholtzii var. eximius, R. eschscholtzii var. oxynotus, R. eschscholtzii var. suksdorfii, R. eschscholtzii var. trisectus
Key
1. Ultimate segments and sinuses of basal leaves acute or acuminate.
→ 2
1. Ultimate segments and sinuses of basal leaves rounded or obtuse (sometimes broadly rounded-acute).
→ 3
2. Leaf blade reniform, base truncate or cordate.
var. suksdorfii
2. Leaf blade obovate to broadly oblong, base obtuse or rounded.
var. eximius
3. Middle segments of many basal leaves lobed and toothed or 2×-lobed.
var. trisectus
3. Middle segments of basal leaves unlobed or 1×-lobed.
→ 4
4. Caudices with few or no persistent leaf bases; basal leaves always 3-parted; widespread in w North America.
var. eschscholtzii
4. Caudices densely clothed with persistent leaf bases; basal leaves sometimes parted but usually merely lobed; California and w Nevada.
var. oxynotus
Name authority L. D. Benson: Amer. Midl. Naturalist 52: 341. (1954) Schlechtendal: Animadv. Bot. Ranunc. Cand. 2: 16. (1820)
Source FNA vol. 3. Treatment author: Alan T. Whittemore. FNA vol. 3. Treatment author: Alan T. Whittemore.
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