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Ranunculus austro-oreganus

southern Oregon buttercup

common water plantain buttercup, kidney-leaf buttercup, plantain-leaf buttercup, water-plantain buttercup

Roots

never tuberous.

slender or fusiform-thickened basally, glabrous.

Stems

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

erect or ascending, not rooting nodally, glabrous or hirsute.

Leaves

basal leaf blades with base acute;

proximal cauline leaf blades lanceolate, ovate, or elliptic, 1.8-14.1 × 0.7-2.9 cm, base acuminate to rounded, margins entire or serrulate, apex obtuse to acuminate.

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.

Inflorescences

bracts lanceolate.

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 5, spreading or reflexed from base, 2-6 × 1-4 mm, glabrous or hirsute;

petals 5-12, 5-14 × 2-8 mm;

nectary scales 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 hemispheric to globose, 3-7 × 4-8 mm;

achenes 1.6-2.8 × 1.2-2 mm, glabrous or rarely hispid;

beak lance-subulate, straight or weakly curved, 0.4-1.2 mm.

Ranunculus austro-oreganus

Ranunculus alismifolius

Phenology Flowering spring (May).
Habitat Grassy hillsides
Elevation 500 m [1600 ft]
Distribution
from FNA
OR
[WildflowerSearch map]
from FNA
CA; CO; ID; MT; NV; OR; UT; WA; WY; BC
[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 (6 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. Flammula
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. 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. alismifolius var. alismellus, R. alismifolius var. alismifolius, R. alismifolius var. davisii, R. alismifolius var. hartwegii, R. alismifolius var. lemmonii, R. alismifolius var. montanus
Key
1. Petals 7–12 on most flowers, 2–3 mm broad.
var. montanus
1. Petals 4–6(–8), 2–8 mm broad.
→ 2
2. Stems 3.5–8 mm thick; leaf margins serrulate.
var. alismifolius
2. Stems 1–3 mm thick; leaf margins entire.
→ 3
3. Leaf blades ovate or elliptic.
var. alismellus
3. Leaf blades broadly to narrowly lanceolate.
→ 4
4. Petals 10–14 mm; California and Nevada.
var. lemmonii
4. Petals 5–8 mm; widespread.
→ 5
5. Roots fusiform-thickened proximally; stems and petioles glabrous or pubescent.
var. davisii
5. Roots not or scarcely fusiform-thickened proximally; stems and petioles glabrous.
var. hartwegii
Name authority L. D. Benson: Amer. Midl. Naturalist 52: 341. (1954) Geyer ex Bentham: Pl. Hartw., 295. (1849)
Source FNA vol. 3. Treatment author: Alan T. Whittemore. FNA vol. 3. Treatment author: Alan T. Whittemore.
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