Flora of the Canadian Arctic Archipelago

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S.G. Aiken, M.J. Dallwitz, L.L. Consaul, C.L. McJannet, R.L. Boles, G.W. Argus, J.M. Gillett, P.J. Scott, R. Elven, M.C. LeBlanc, L.J. Gillespie, A.K. Brysting, H. Solstad, and J.G. Harris

Ranunculus L.

English: Buttercups.

Ranunculaceae, Buttercup family.

Published in Sp. Pl. 548. 1753.

Vegetative morphology. Plants 1–45 cm high; perennial herbs; caespitose, or not caespitose; not glandular viscid. Only fibrous roots present. Ground level or underground stems horizontal, or vertical, or absent; rhizomatous, or stoloniferous; elongate, or compact; 0.4–2 mm wide. Caudex present, or absent. Aerial stems erect, or decumbent, or prostrate. Aerial stem trichomes appressed, or spreading, or erect. Leaves heterophyllous, or not heterophyllous; mainly basal, or distributed along the stems, or arising singly from creeping rhizomes, or basal in a rosette; alternate; dying annually and non-persistent. Stipules absent. Petioles present; 4–90 mm long; glabrous. Leaf blades simple. Leaf blade bases cordate, or truncate, or obtuse, or attenuate, or rounded. Blades (3–)6–20(–65) mm long, 3–35 mm wide, spreading, linear or oblong or elliptic or circular or ovate or obovate or reniform or triangular, flat, with three main veins or veins palmate. Blade adaxial surface dull, glabrous or glabrescent or hairy, hairs simple. Blade abaxial surface hairy, hairs pilose or villous, hairs sparse, hairs white. Blade margins flat, blades lobed or not lobed. Blade margins entire or crenate, glabrous or with non-glandular hairs, with teeth toward the apex. Hydathodes present but inconspicuous. Blade apices acuminate, or acute, or obtuse, or rounded.

Reproductive morphology. Flowering stems shorter than the leaves, or conspicuously taller than the leaves; with leaves, or without leaves. Flowers solitary, or in inflorescences. Inflorescences without bulbils; cymose. Inflorescences main axis glabrous. Flowers per inflorescence 1–3(–7); small, or medium-sized, or large. Sepals conventional; 3–5; free; 1–7 mm long; (2–)3–6(–13) mm wide; green, or yellow, or brown, or purple; herbaceous, or scarious. Calyx glabrous, or hairy. Calyx hairs pubescent; white or translucent, or brown. Petals conventional; free; same length as the calyx, or longer than the calyx; 3–9(–11); white, or yellow; obovate, or oblanceolate; unlobed; 2.5–12(–15) mm long; 1–5(–9) mm wide. Stamens 8–35; stamen filaments all equal in length; stamen filaments glabrous; free of the corolla. Anthers yellow; ellipsoid; 0.8–1–1.2 mm long. Nectaries present. Receptacle 1–12 mm high; surface glabrous, or hairy. Ovary carpels 11–100; apocarpous. Ovaries elliptic; abruptly tapering to style; glabrous, or hairy. Styles 0.1–0.4 mm long. Stigmas per ovary 1. Placentation parietal. Ovules per ovary 1. Fruit sessile; stalk 2–11 mm long; dry; an aggregate of achenes (individual achenes smooth, flattened and tipped with a persistent style); spherical, or ovoid, or elongate-cylindrical, or obovate; yellowish, or black, or purple, or green at maturity; 1–7(–15) mm long; 0.8–15 mm wide; glabrous, or hairy; surface venation reticulate; distinctly flattened; indehiscent. Styles remaining straight; persisting in fruit 0.2–1.2 mm long. Seeds 1.

Chromosome information. 2n = 16, or 32, or 48, or 64.

North American distribution. Range in the Canadian Arctic Archipelago widespread, or limited. Common, uncommon, rare. Arctic, High Arctic, Low Arctic, alpine, boreal. Arctic islands: Baffin, Devon, Ellesmere, Axel Heiberg, Parry islands, Cornwallis, Banks, Victoria, Prince of Wales, Somerset, King William.

General notes. Some authors (e.g., Elven et al. 2003) recognise several segregate genera besides Ranunculus s.s., e.g., Oxygraphis Bunge with the Asian and amphi-Beringian O. glacialis (Fisch.) Bunge (Ranunculus kamchaticus DC.) eastwards to Alaska, Beckwithia Jeps. with, e.g., the arctic and amphi-atlantic B. glacialis (L.) Á. Löve and D. Löve (Ranunculus glacialis L.) westwards to Greenland, and the amphi-Beringian B. camissonis (Schltdl.) Tolm. (Ranunculus camissonis Schltdl.) eastwards to Yukon, Coptidium (Nyman) Tzvelev with C. lapponicum (L.) Tzvelev (Ranunculus lapponicus L.) and C. pallasii (Schltdl.) Tzvelev (Ranunculus pallasii Schltdl.), and Batrachium (DC.) Gray with, e.g., B. eradicatum (Laest.) Fr. (for Ranunculus synonym(s), see below). These segregates have not been taken up by the Flora of North America treatment (Whittemore 1997).

Benson (1948) observed that the presence of the scale covering the nectary on the ventral side of the base of the petal blades in Ranunculus was known to Linnaeus who had observed that the nectary scale is, in some species, a naked pore; in some it is bordered with cylindrical margins; in others it is closed with a notched scale. The scale is absent in subgenus Batrachium or present only as a simple round type. Benson claimed his study of Ranunculus revealed six types of scales.

1. a transverse ridge basal to the gland,

2. a simple flap,

3. a pocket,

4. a forked structure produced distally and sometimes finally free from the petal at the tips of the two branches of the scale,

5. a circular or obovate border,

6. differentiation of a primary scale which bears the gland on its ventral surface, and of a secondary scale which forms a pocket enclosing the gland.

Scales of any of the six types may be proximally truncate, rounded, or angular and distally truncate, emarginate, 3-lobed, curved outward, or curved inward. Commonly, the scale is glabrous, but in some species the distal margin is ciliate, and sometimes the neighbouring surface of the petal also produces hairs. Basic types almost consistently characterise the subgenera and sections of the genus.


This publication is available on the internet (posted May 2011) and on CD-ROM (published in 2007). These versions are identical in content, except that the errata page for CD-ROM is accessible on the main index page of the web version.

Recommended citation for the web-based version of this publication: Aiken, S.G., Dallwitz, M.J., Consaul, L.L., McJannet, C.L., Boles, R.L., Argus, G.W., Gillett, J.M., Scott, P.J., Elven, R., LeBlanc, M.C., Gillespie, L.J., Brysting, A.K., Solstad, H., and Harris, J.G. 2007. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. NRC Research Press, National Research Council of Canada, Ottawa. http://nature.ca/aaflora/data, accessed on DATE.

Recommended citation for the CD-ROM version of this publication: Aiken, S.G., Dallwitz, M.J., Consaul, L.L., McJannet, C.L., Boles, R.L., Argus, G.W., Gillett, J.M., Scott, P.J., Elven, R., LeBlanc, M.C., Gillespie, L.J., Brysting, A.K., Solstad, H., and Harris, J.G. 2007. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. [CD-ROM] NRC Research Press, National Research Council of Canada, Ottawa.

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