Ranunculus orthorhynchus
Ranunculus sect. Ranunculus
Bloomer's buttercup, straight-beak buttercup, swamp buttercup
sometimes fleshy and ± tuberous.
basal, sometimes also nodal, sometimes tuberous.
nearly erect or decumbent, never rooting nodally, hispid, strigose, or glabrous, base not bulbous.
erect to decumbent, sometimes stoloniferous, sometimes bulbous-based, without bulbils.
basal and cauline, petiolate;
basal deeply parted or compound (except sometimes in R. orthorhynchus var. bloomeri), blades with segments lobed or parted, margins toothed;
cauline deeply parted or compound, similar to basal or with shorter petioles and/or blades with narrower segments (rarely poorly developed in R. fascicularis).
blades 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.
1-50-flowered cymes.
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.
pedicellate;
sepals deciduous soon after anthesis, 5 (sometimes 6 in R. occidentalis var. hexasepalus);
petals always present, yellow, sometimes abaxially reddish, rarely poorly developed;
nectary scale attached basally, free from petal for at least 1/2 its length, forming flap covering nectary (or sometimes attached on 3 sides, forming pocket in R. recurvatus), glabrous, free margin entire;
style present.
achenes, 1-locular;
achene body discoid, strongly flattened, 3-15 times as wide as thick, not prolonged beyond seed;
wall thick, not ornamented;
margin low or high narrow ridge or wing;
beak much shorter than achene body.
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 orthorhynchus
Ranunculus sect. Ranunculus
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.)
Species ca. 100 (19 in the flora).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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 |
1. Petals 2-6 mm, usually no longer than sepals (sometimes longer than sepals in R. uncinatus). | → 2 |
1. Petals (6-)7-26 mm (rarely shorter in R. occidentalis and R. canus, in which petals are much longer than sepals). | → 5 |
2. Basal leaves simple and lobed or parted. | → 3 |
2. Basal leaves compound. | → 4 |
3. Receptacle glabrous; base of stem not bulbous; w North America. | R. uncinatus |
3. Receptacle hispid; base of stem bulbous, cormlike; e North America. | R. recurvatus var. recurvatus |
4. Petals 2-4 × 1-2.5 mm; heads of achenes cylindric, 5-7 mm wide. | R. pensylvanicus |
4. Petals 4-6 × 3.5-5 mm; heads of achenes globose to ovoid, 7-10 mm wide. | R. macounii |
5. Sepals spreading, sometimes reflexed from base with age. | → 6 |
5. Sepals reflexed along well-defined transverse fold 1-3 mm above base. | → 12 |
6. Basal leaves deeply parted or dissected, ultimate segments linear to broadly linear, margins entire (occasionally a lobe reduced to large tooth); Rocky Mountains. | R. acriformis var. acriformis |
6. Basal leaves variously parted or compound but not as above, segments seldom linear, margins toothed; widespread. | → 7 |
7. Leaf blades simple, 3-5-parted or -divided. | → 8 |
7. Leaf blades 3-5-foliolate. | → 9 |
8. Basal leaf blades pentagonal in outline; beak of achene 0.2-1 mm; widespread. | R. acris |
8. Basal leaf blades cordate to reniform in outline; beak of achene 1.6-2 mm; Mackenzie Delta to ne Alaska. | R. turneri |
9. Tuberous roots present. | → 10 |
9. Tuberous roots absent. | → 11 |
10. Petals 10-22; c Texas. | R. macranthus |
10. Petals 5(-7); widespread, e North America. | R. fascicularis |
11. Beak of achene curved, 0.8-1.2 mm; stems decumbent to creeping. | R. repens |
11. Beak of achene straight or somewhat curved, 0.8-2.6 mm; stems erect to decumbent. | R. hispidus |
12. Petals 8-22; Pacific Coast, Arizona, Texas. | → 13 |
12. Petals 5-7; widespread. | → 17 |
13. Tuberous roots absent; beak of achene lanceolate to deltate-apiculate, curved, 0.2-1.6 mm; California to British Columbia. | → 14 |
13. Tuberous roots present; beak of achene subulate, straight, (1.8-)2-4 mm (but sometimes deciduous); Texas, Arizona. | → 16 |
14. Achenes 3.4-4.2 mm, beak deltate or lance-deltate; Transverse Ranges, s California. | R. canus var. ludovicianus |
14. Achenes 1.8-3.2 mm, beak lanceolate; California to British Columbia. | R. californicus |
15. Beak of achene 1.2-1.6 mm; sepals 5-6; Queen Charlotte Islands, British Columbia. | R. occidentalis var. hexasepalus |
15. Beak of achene 0.2-0.8 mm; sepals 5; California, Oregon, Mexico. | R. californicus |
16. Petals 2-5 mm wide; achenes 2-2.4 mm wide, margins forming ribs or narrow wings 0.1-0.4 mm wide; sepals always reflexed; Arizona, trans-Pecos Texas. | R. fasciculatus |
16. Petals 4-9 mm wide; achenes 2.8-3.4 mm wide, margins forming narrow ribs 0.4-0.6 mm wide; sepals spreading or weakly reflexed; Edwards Plateau, Texas. | R. macranthus |
17. Receptacle glabrous; basal leaves 3-parted or -foliolate, segments or leaflets linear to cuneate. | → 18 |
17. Receptacle hispid; basal leaves usually pinnately 3-7-foliolate (sometimes merely 3-parted with orbiculate to ovate segments in Ranunculus orthorhynchus var. bloomeri). | → 21 |
18. Beak of achene deltate or lance-deltate, curved; Sacramento Valley, California. | R. canus var. canus |
18. Beak of achene lanceolate to lance-subulate, straight or curved; widespread. | → 19 |
19. Basal leaves deeply 3-divided, segments again deeply parted, ultimate segments linear or nearly so; Rocky Mountains. | R. acriformis var. montanensis |
19. Basal leaves deeply 3-parted to 3-foliolate, margins of segments or leaflets toothed or shallowly lobed, ultimate lobe triangular or broadly lanceolate; Pacific Slope. | → 20 |
20. Petals yellow on both surfaces; widespread. | R. occidentalis |
20. Petals reddish abaxially; sw Oregon. | R. austro-oreganus |
21. Beak of achene oblong or triangular, curved, 0.2-0.8 mm; introduced weeds. | → 22 |
21. Beak of achene lanceolate or subulate, straight or somewhat curved (sometimes tip weakly hooked in R. pacificus), (0.8-)1-3.8(-4.8) mm; native. | → 23 |
22. Base of stem bulbous, cormlike; petals 9-13 × 8-11 mm. | R. bulbosus |
22. Base of stem not bulbous; petals 7-10 × 4-8 mm. | R. sardous |
23. Stems decumbent, sometimes rooting at nodes; e North America. | R. hispidus var. nitidus |
23. Stems erect to decumbent, never rooting at nodes; w North America. | → 24 |
24. Beak of achene 1-1.8 mm; leaflets lobed; Alaska panhandle. | R. pacificus |
24. Beak of achene 2-3.8(-4.8) mm (1.8-2.2 mm in var. bloomeri, with unlobed leaflets); throughout w North America. | R. orthorhynchus |
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PNW Herbaria, Turner Photog. 
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