Ranunculus sect. Echinella
basal, never tuberous.
erect or decumbent, not bulbous-based, without bulbils.
basal and cauline or sometimes only cauline;
basal and lower cauline leaves similar, petiolate, blades undivided, lobed, or compound, segments lobed or unlobed, margins entire or dentate.
2-16-flowered cymes (cymes sometimes sympodial, then flowers seemingly inserted opposite bracts).
pedicellate (sessile in R. platensis);
sepals deciduous soon after anthesis, 5 (3 in R. platensis);
petals yellow (sometimes absent in R. hebecarpus);
nectary scale attached basally, free from petal for at least 1/2 its length, forming flap covering nectary, glabrous, free margin entire;
style present.
achenes, 1-locular;
achene body discoid, strongly flattened, 3-7 times as wide as thick, not prolonged beyond seed;
wall thick, spiny, tuberculate, or papillose (sometimes smooth in R. sardous);
margin low or high, broad or narrow ridge;
beak much shorter than achene body.
Ranunculus sect. Echinella
Species ca. 15 (8 in the flora).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Petals 1–2 mm; achenes finely papillose, papillae terminating in slender hooked hairs or spines; native or introduced. | → 2 |
1. Petals 4–10 mm; achenes coarsely papillose, tuberculate, or spinose, rarely smooth; introduced weeds. | → 4 |
2. Flowers sessile; sepals 3. | R. platensis |
2. Flowers pedicellate; sepals 5. | → 3 |
3. Achenes ornamented on faces and margin, with lanceolate beaks; native of Pacific Slope. | R. hebecarpus |
3. Achenes ornamented on faces but not margin, with deltate beaks; introduced weed, widespread in North America. | R. parviflorus |
4. Sepals spreading; achenes 5–9 in single whorl, the faces and margin long-spinose. | R. arvensis |
4. Sepals reflexed; achenes 10–60 in ovoid or globose heads, the faces papillose to spinose or rarely smooth, margin smooth. | → 5 |
5. Basal leaves compound; achene beak 0.3–0.7 mm. | → 6 |
5. Basal leaves simple; achene beak 1–2.5 mm. | → 7 |
6. Achene faces sparsely papillate or sometimes smooth; petals more than 5 mm. | R. sardous |
6. Achene faces densely tuberculate; petals less than 5mm. | R. trilobus |
7. Achene faces but not margin covered with long spines; beaks 2– 2.5 mm. | R. muricatus |
7. Achene faces but not margin covered with high sharp tubercles or low spines; beaks ca. 1 mm. | R. marginatus |
