Flora of the Canadian Arctic Archipelago


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

Potentilla nivea L.

English: Snow cinquefoil,

French: Potentille de seiges.

Rosaceae, Rose family.

Published in Nom. cons. prop., Sp. Pl. 499. 1753.

Type: Sweden: Torne Lappmark, Abisko area, Latnjajaure, Eriksen 620, selected by Eriksen et al. Taxon 48, 165. 1999. Neotype cons. prop. GB.

Synonymy. Potentilla prostrata Rottb., Skr. Kiøbenhavnske Selsk. Lærd. Elsk. 10: 453. 1770.

Potentilla nivea L. var. pallidior Sw., Summa Veg. Scand. 19. 1814.

Potentilla prostrata Rottb. subsp. floccosa Soják, Candollea, 44: 751. 1989.

Vegetative morphology. Plants (4–)8–20(–30) cm high; perennial herbs; caespitose. Taproot present (about 2.5 mm thick). Ground level or underground stems vertical; 3–10 mm wide. Caudex present (short, with leaf crown and lateral peduncles). Aerial stems branching from a tap at or near ground level into two or more branches; erect, or ascending. Leaves mainly basal; alternate; dying annually and non-persistent and marcescent (petioles and stipules marcescent). Stipules present; (4–)6–10(–12) mm long; (1.2–)1.5–3(–4) mm wide; not sheathing; green (and often pinkish when fresh, dark reddish brown when marcescent); hairy; pilose and villous; glandular (slightly); apex acute. Petioles (10–)30–60(–100) mm long; hairy; woolly (floccose, very rarely also with a few long (pilose) hairs). Petiole hairs shorter than the diameter of the petiole; appressed; floccose; smooth, or rough (long hairs). Leaf blades compound. Blades (8–)10–20(–30) mm long, (10–)15–25(–35) mm wide, veins palmate (leaflet veins pinnate). Blade adaxial surface with sessile glands, glabrous or glabrescent or hairy (sparse to dense rarely), hairs pilose or long-silky (sometimes), hairs sparse or moderately dense, hairs white, or translucent. Blade abaxial surface dull (when visible), hairy, hairs long-silky (on midvein) or woolly (surface floccose between veins), hairs very dense, hairs white, hairs wavy, hairs appressed. Blade margins crenate or dentate, with non-glandular hairs, with 3–5(–10) teeth on each side of the blade (very rarely), with teeth all around the blade or toward the apex; degree of incision 20–50%; apices rounded. Leaflet arrangement palmate (very rarely with 1–2 small additional leaflets). Leaflets 3(–5) (very rarely more than three in Canadian plants); (8–)10–20(–30) mm long; (5–)7–12(–15) mm wide; elliptic, or obovate; veins conspicuous (on adaxial surface, often visible on the abaxial surface). Apical leaflet base not distinctly stipitate, or distinctly stipitate; stipe 0–1(–4) mm long.

Reproductive morphology. Plants agamospermic, or bisexual (possibly). Flowering stems two or more per plant; conspicuously taller than the leaves; with leaves. Flowering stems hairy. Flowering stems woolly (floccose). Flowering stem hairs simple; shorter than the diameter of the flowering stem; white or translucent. Flowers in inflorescences, or solitary (rarely, in very small plants). Inflorescences cymose; diffuse. Pedicels present. Flowers per inflorescence (1–)2–4(–7); medium-sized, or large. Sepals conventional. Epicalyx present. Epicalyx segments (3–)4–5(–6) mm long. Epicalyx segments (0.8–)0.9–1.1(–1.2) mm wide. Epicalyx segments shorter than the calyx segments, or equal in length to the calyx segments. Epicalyx segments narrower than the calyx segments (conspicuously so). Sepals 5; free; (1.8–)2–3(–3.2) mm long; (3–)4–6(–7) mm wide; green (sometimes reddish); accrescent. Calyx with sessile glands; hairy. Calyx hairs pilose, or villous, or long-silky; white or translucent. Calyx margins without cilia. Petals conventional; free; 5; yellow; without contrasting markings; obovate; slightly lobed or undulating; (4–)6–8(–10) mm long; (5–)7–9(–11) mm wide. Stamens 20–30; stamen filaments glabrous. Anthers yellow; ellipsoid, or triangular; 0.4–0.5 mm long. Ovary superior; carpels 25–40; apocarpous. Styles 0.8–1.2 mm long; straight; basal portion covered with short papillae, less than 0.1 mm high (in most, or all Canadian Arctic Archipelago specimens, often nearly smooth in northern European plants). Ovules per ovary 1. Fruit sessile; with calyx persisting; dry; an aggregate of achenes; ovoid; green at maturity, or straw-coloured; 0.9–1.2 mm long; 0.5–0.8 mm wide; glabrous; surface appearing veinless; indehiscent.

Chromosome information. 2n = 56 (for P. nivea s.l.); 14–77 (most recorded chromosome numbers are dubious, especially the lower numbers, owing to doubts about the identity of the material).

2n (6x) = 42. Dobes et al. (1997, central Europe, 'nivea');

2n (8x) = 56. Erlandsson (1942b, Sweden, 'nivea'); Müntzing, in Hultén (1945, 'nivea'); Dansereau and Steiner (1956, northeastern Canada, 'nivea'); Knaben and Engelskjøn (1967, southern Norway, 'nivea'); Engelskjøn (1979, arctic Norway, 2n = 54–56); Löve and Löve (1982a, Arctic Canada);

2n (9x) = 63. Böcher and Larsen (1950, Greenland, 'subquinata'); Knaben and Engelskjøn (1979, northern Norway, 'nivea'); Löve and Löve (1982a, 'nivea'); Dalgaard (1989, western Greenland, 'nivea'). Supposed basic chromosome number of family 7.

Ploidy levels recorded 6x, 8x, and 9x.

Ecology and habitat. Substrates: wet meadows (damp protected sedge meadow, CAN 271339), tundra, slopes, ridges, cliffs, dry meadows; imperfectly drained moist areas (rarely), dry, moderately well-drained areas; rocks, gravel, sand; with low organic content; calcareous, or nitrophilous. Usually found on cliffs, in screes and on coarse-grained ridges and outcrops, mostly on calcareous to circumneutral substrates and always on dry, well-drained ground.

North American distribution. Alaska, Yukon, continental Northwest Territories, Nunavut Islands, continental Nunavut, northern Quebec, Labrador. Range in the Canadian Arctic Archipelago limited. Rare. Low Arctic and boreal. Arctic islands: Baffin, Banks, Victoria, Southampton.

Northern hemisphere distribution. Circumpolar, or circumboreal (arctic-alpine, and depending on circumscription of species). Northern Fennoscandian, Svalbard – Franz Joseph Land, Polar Ural – Novaya Zemlya, Taimyr – Severnaya Zemlya, Anabar–Olenyok, Kharaulakh, Yana–Kolyma, West Chukotka, Wrangel Island, South Chukotka, East Chukotka, North Alaska – Yukon, Central Canada, Labrador – Hudson Bay, Ellesmere Land – Peary Land, West Greenland, East Greenland.

General notes. As defined here, P. nivea is a circumpolar entity. It reaches the High Arctic in Greenland and Svalbard but is distinctly Low Arctic in the Canadian Arctic Islands. The Baffin island plants are uniformly trifoliate and densely tomentose (floccose), with almost no straight hairs, and they match P. nivea L. s.s. The Victoria island plants have some straight hairs and also some other characters that may be indicative of some influence from the P. arenosa subgroup. They differ, however, appreciably from the Beringian entity (P. crebridens or P. nivea subsp. hemicryophila).

The name P. nivea L. subsp. nivea might be applicable for the eastern Canadian plants if the current, mainly genetically based, entities are separated as subspecies. Relations between the Canadian and European plants, and the variation in Greenland, need to be ascertained by genetic investigations before any firm taxonomic and nomenclatural conclusions can be drawn.

Illustrations. • Close-up of plant. Flowering plant in steep lush south-facing slope. This plant has been named as subsp. subquinata (with 3–5 leaflets) and is assumed to be amphi-Atlantic. Norway, Svalbard, Odindalen. August, 1997. Voucher at 0. Photograph by R. Elven. • Close-up of plant. Drawing by Mrs. S. Bergh and Mrs. L. Barstad based on a collection from Svalbard, Nordenskiöld Land, Colbay. 1 August, 1908. H. Resvoll-Dieset (Det. J. Soják 1982 as P. nivea x chamissonis? and as P. cf. subquinata; det. R. Elven 1999 as P. nivea!) O 20403/0 200500/0 200501/0 200608/0 200609 (SJEKK HERB) With permission of the Botanical Museum, University of Oslo, Norway. • Close-up of plant. Note regularly trifoliate leaves, green on upper surface, white-floccose on lower surface. Nunavut, Baffin Island, Iqaluit. CAN 223775. • Close-up of caudex. Strongly developed branching caudex covered with reddish brown stipules and leaf bases. Nunavut, Baffin Island, Beechman Peninsula. CAN 284041. • Close-up of trifoliate leaf. Lower leaf surface white-floccose, terminal leaflet sessile or very short-stipitate. Nunavut, Baffin Island, Kimmirut. CAN 72476. • Close-up of flower. Dark brown-green, narrow epicalyx segments, pale green wider calyx segments and notched petals that are distinctly longer than the calyx. Nunavut, Baffin Island, Iqaluit. CAN 223775. • Arctic Island Distribution.

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.