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Ranunculus austro-oreganus

southern Oregon buttercup

Roots

never tuberous.

fleshy and somewhat tuberous.

Stems

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

erect or decumbent, not rooting nodally, hirsute to nearly glabrous, 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.

ovate to deltate in outline, 3(-5)-foliolate, 2.5-14.9 × 2.3-19.9 cm, leaflets 1-2x-lobed or -parted, ultimate segments narrowly oblong to elliptic or lanceolate, margins toothed, apex narrowly acute to 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 hispid;

sepals reflexed 1-2 mm above base, 5-10 × 3-5 mm, hispid;

petals 11-16, yellow, 8-21 × 2-5 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 globose to ovoid, 6-13 × 7-9 mm;

achenes 2.4-3.4 × 2-2.4 mm, glabrous, margin forming rib or narrow wing 0.1-0.4 mm wide;

beak filiform from deltate base, straight, 1.8-2.5 mm, filiform tip often deciduous, leaving 1-1.2 mm deltate beak.

Ranunculus austro-oreganus

Ranunculus fasciculatus

Phenology Flowering spring (May). Flowering late spring–summer (Jun–Aug).
Habitat Grassy hillsides Stream banks, lakeshores, and marshes
Elevation 500 m [1600 ft] 1000-2200 m [3300-7200 ft]
Distribution
from FNA
OR
[WildflowerSearch map]
from FNA
AZ; TX; Mexico
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.)

I am following G. L. Nesom (1993) in treating Ranunculus fasciculatus as a distinct species. This taxon was considered a variety of R. macranthus by L. D. Benson (1948) and a variety of R. petiolaris by T. Duncan (1980). These disparate opinions result from different interpretations of Mexican members of the R. petiolaris group.

(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. 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. eschscholtzii, R. fascicularis, 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
Synonyms R. macranthus var. arsenei, R. petiolaris
Name authority L. D. Benson: Amer. Midl. Naturalist 52: 341. (1954) Sessé & Moçiño: Fl. Mexic. ed. 2, 134. (1894)
Source FNA vol. 3. Treatment author: Alan T. Whittemore. FNA vol. 3. Treatment author: Alan T. Whittemore.
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