The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

margined buttercup

Bloomer's buttercup, straight-beak buttercup, swamp buttercup

Roots

sometimes fleshy and ± tuberous.

Stems

erect, sparsely pilose.

nearly erect or decumbent, never rooting nodally, hispid, strigose, or glabrous, base not bulbous.

Basal leaf blades

reniform to semicircular, undivided or shallowly 3-lobed, 2.5-5 × 3-7 cm, base truncate to nearly cordate, margins crenate or dentate, apex rounded or obtuse.

narrowly ovate to oblong or semicircular in outline, simple to 3-5-lobed or -foliolate, 2.8-12.5 × 2.5-14 cm, leaflets or segments undivided or 1-2x-lobed or -parted, ultimate segments circular to linear, margins dentate, crenate, or entire, apex rounded to narrowly acute.

Flowers

pedicellate;

receptacle hispid;

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

petals 5, 4-5 × 2-3.5 mm.

receptacle hispid;

sepals reflexed 1-2 mm above base, 5-11 × 2-4 mm, hispid, hirsute, or glabrous;

petals 5-6, abaxially yellow or red, adaxially yellow, 8-18 × 4-11 mm.

Heads of achenes

hemispheric to globose, 4 × 6 mm;

achenes 15-20 per head, 2.5-3 × 2-2.5 mm, faces covered with high sharp tubercles or low spines, glabrous, margin smooth;

beak deltate, straight, 0.8-1 mm.

hemispheric to ovoid, 5-13 × 6-10 mm;

achenes 2.8-4.5 × 1.8-3.2 mm, glabrous, margin forming narrow rib 0.1-0.2 mm wide;

beak persistent, narrowly lanceolate to subulate, straight, 1.8-3.8(-4.8) mm.

Ranunculus marginatus

Ranunculus orthorhynchus

Phenology Flowering spring (Mar–May).
Habitat Roadsides
Elevation 0-100 m (0-300 ft)
Distribution
from FNA
AL; LA; TX; native to Europe [Introduced in North America]
[BONAP county map]
from FNA
AK; CA; ID; MT; NV; OR; UT; WA; WY; BC
[WildflowerSearch map]
[BONAP county map]
Discussion

A form of Ranunculus marginatus, with the fruits weakly tuberculate or almost smooth, similar to the smooth-fruited forms of R. sardous, is found in Europe; it is not known from North America.

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

Varieties 3

The first two varieties (Ranunculus orthorhynchus var. orthorhynchus and R. orthorhynchus var. platyphyllus) are rather weak, intergrading extensively in California and Oregon. By contrast, R. orthorhynchus var. bloomeri often grows with the others with little or no intergradation (although intermediate populations are found in some areas), and it has been treated as a distinct species, R. bloomeri, by many taxonomists.

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

Key
1. Basal leaves simple or 3-foliolate, if compound then leaflets undivided, margins crenate; petals retuse.
var. bloomeri
1. Basal leaves 3–5-foliolate, leaflets lobed or parted, margins entire or dentate; petals truncate or rounded.
→ 2
2. Heads of achenes hemispheric or sometimes globose, 5–7 mm; petals often abaxially red.
var. orthorhynchus
2. Heads of achenes globose or ovoid, 8–13 mm; petals yellow.
var. platyphyllus
Source FNA vol. 3. FNA vol. 3.
Parent taxa Ranunculaceae > Ranunculus > subg. Ranunculus > sect. Echinella 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. 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. 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. 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. 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. orthorhynchus var. bloomeri, R. orthorhynchus var. orthorhynchus, R. orthorhynchus var. platyphyllus
Name authority d'Urville: Mém. Soc. Linn. Paris 1: 318. (1822) Hooker: Fl. Bor.-Amer. 1: 21. (1829)
Web links