Flora of the Canadian Arctic Archipelago
Rosaceae, Rose family.
Published in In Kom., Fl. URSS 10: 137. 1941.
Type: Described from Siberia: Transbaikal.
Synonymy. Potentilla nivea L. var. arenosa Turcz., Bull. Soc. Imp. Naturalistes Moscou 16: 607. 1843.
Potentilla hookeriana auct., non Lehm. 1849.
Potentilla nivea sensu Soják. 1989, non L. (1753) emend. Eriksen et al. (1999).
?Potentilla nipharga Rydberg, N. Amer. Fl. 22: 332. 1908.
?Potentilla nivea sensu Soják var. nipharga (Rydberg) Soják, Candollea 44: 751. 1989.
?Potentilla arenosa (Turcz.) Juz. var. nipharga (Rydberg) Jurtz. ined.
Vegetative morphology. Plants 5–25(–35) cm high; perennial herbs; caespitose. Taproot present. Ground level or underground stems vertical; 5–10 mm wide. Caudex present. 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; (6–)8–12(–14) mm long; 1.5–3.5(–4) mm wide; not sheathing; green (or hyaline when fresh, reddish brown when marcescent); hairy; pilose; glandular, or without glands; apex acuminate, or acute. Petioles 5–40(–80) mm long; without sessile glands, or with sessile glands; hairy; pubescent and pilose (with long, straight or ascending, stiff, verrucose hairs and a denser cover of short sub-appressed to ascending, thin, stiff hairs). Petiole hairs shorter than the diameter of the petiole and longer than the diameter of the petiole; appressed and spreading; straight; rough (the long pilose hairs). Leaf blades compound. Blades 5–20(–40) mm long, 8–25(–50) mm wide, veins palmate (leaflet veins pinnate). Blade adaxial surface without sessile glands, hairy, hairs pilose or long-silky (nearly always scattered and appressed pilose, sometimes also with silky sub-appressed hairs, especially towards apex of leaflets), hairs simple, hairs sparse or moderately dense (rarely), hairs white, or translucent. Blade abaxial surface dull (when visible), hairy, hairs tomentose (between veins) or long-silky (on veins), hairs very dense, hairs white, hairs straight or wavy, hairs appressed (short hairs) or spreading (long hairs). Blade margins dentate or deeply divided, with non-glandular hairs, with 3–6(–7) teeth on each side of the blade, with teeth all around the blade; degree of incision (30–)40–70(–80)%; apices rounded. Leaflet arrangement palmate, or digitate (rarely). Leaflets 3(–5); 7–15(–30) mm long; 7–13(–20) mm wide; elliptic, or obovate; veins conspicuous. Apical leaflet base distinctly stipitate; stipe 1–4(–7) mm long.
Reproductive morphology. Plants agamospermic (agamospermous), or bisexual (possibly). Flowering stems two or more per plant; conspicuously taller than the leaves; with leaves. Flowering stems hairy. Flowering stems pilose, or pubescent. Flowering stem hairs simple; shorter than the diameter of the flowering stem, or longer than the diameter of the flowering stem; white or translucent. Flowers in inflorescences (rarely solitary). Inflorescences cymose; lateral (on caudex); diffuse. Pedicels present. Flowers per inflorescence (1–)3–5(–15); medium-sized, or large, or small (rarely). Sepals conventional. Epicalyx present. Epicalyx segments (2–)3–6(–8) mm long. Epicalyx segments 0.4–0.8(–1) mm wide. Epicalyx segments equal in length to the calyx segments, or shorter than the calyx segments. Epicalyx segments narrower than the calyx segments (conspicuously narrower). Sepals 5; free; 2–2.5 mm long; (4–)5–8(–10) mm wide; green; non-accrescent. Calyx with sessile glands; hairy (long hairs). Calyx hairs pilose, or long-silky; white or translucent. Calyx margins without cilia. Petals conventional; free; 5; yellow; obovate; slightly lobed or undulating (distinctly notched); (4–)5–8 mm long; 5–9 mm wide. Stamens 15–25(–30); stamen filaments glabrous. Anthers yellow; ellipsoid, or triangular; 0.4–0.5(–0.6) mm long. Ovary superior; carpels 25–35; apocarpous. Styles 0.7–1 mm long; straight; basal portion covered with short papillae, less than 0.1 mm high. Ovules per ovary 1. Fruit sessile; with calyx persisting; dry; an aggregate of achenes; ovoid; green at maturity, or straw-coloured; 0.8–1.2 mm long; 0.5–0.8 mm wide; glabrous; surface venation reticulate, or venation ribbed; indehiscent.
Chromosome information. 2n = 28, or 42, or 49, or 56, or 70.
2n (4x) = 28. Johnson and Packer (1968, northwestern Alaska); Zhukova and Petrovsky (1975, 1980, western Chukotka; 1985b, north and northeastern Asia); Krogulevich (1976a, northern Siberia, as P. kuznetzovii); Yurtsev and Zhukova (1982, northern Siberia);
2n (6x) = 42. Popoff (1939, as P. arenosa); Christoff and Papasova (1943, as P. arenosa); Zhukova and Petrovsky (1971, Wrangel Island; 1976, 1980, western Chukotka; 1985b, north and northeastern Asia); Krogulevich (1976a, northern Siberia, as P. kuznetzovii); Yurtsev and Zhukova (1982, northern Siberia);
2n (7x) = 49. Zhukova and Petrovsky (1972, 1980, western Chukotka; 1985b, north and northeastern Asia);
2n (8x) = 56. Zhukova and Petrovsky (1987b, northeastern Asia);
2n (10x) = 70. Krogulevich (1971, southern Siberia); Zhukova (1980, southern Chukotka); Petrovsky and Zhukova (1981, Wrangel Island); Zhukova and Petrovsky (1985b, north and northeastern Asia). Supposed basic chromosome number of family 7.
Ploidy levels recorded 4x, 6x, 7x, 8x, 10x.
Ecology and habitat. Substrates: river terraces, tundra (CAN 72592), slopes, ridges, cliffs, dry meadows; dry, moderately well-drained areas; rocks, gravel, silt; with low organic content, with high organic content (rarely, bird perches); calcareous, or nitrophilous. A decidedly calciphilous taxon in the Arctic. Lack of basic substrates may be compensated for locally by bird manuring. Both subspecies of P. arenosa (and many other Potentilla species) are nearly constant inhabitants of bird perches.
North American distribution. Alaska, Yukon, Northwest Territories Islands, continental Northwest Territories, Nunavut Islands, continental Nunavut. Range in the Canadian Arctic Archipelago widespread. Common. Arctic, alpine, and boreal. Arctic islands: Devon, Ellesmere, Axel Heiberg, Parry islands (Emerald, Melville), Banks, Victoria.
Northern hemisphere distribution. Amphi-Beringian (broadly). KaninPechora, Polar Ural Novaya Zemlya, Taimyr Severnaya Zemlya, AnabarOlenyok, Kharaulakh, YanaKolyma, West Chukotka, Wrangel Island, South Chukotka, East Chukotka, West Alaska, North Alaska Yukon, Central Canada, Ellesmere Land Peary Land, West Greenland, East Greenland.
General notes. The name P. arenosa is accepted over P. hookeriana after a reconsideration of the types (Elven, personal communication, 2005). Jurtsev and Soják (personal communication) have long asserted that Lehmann's type of P. hookeriana, which has a restricted distibution in the southern Cordilleran, is possibly a hybrid, and is inapplicable for the widespread arctic-boreal plant(s). Bente Eriksen (personal communication) has also studied the type and concurs. This means that the priority name must be P. arenosa, if we consider the Russian and the American plants as the same, which we do.
This is a circumpolar taxon that is very common in both the high and Low Arctic parts and often with isolated occurrences in temperate mountains.
At least six names at species level have been considered within this group of races or closely related species: P. hookeriana (1849 described from western North America), P. nipharga (1908), P. arenosa (1941) (described as a variety of P. nivea in 1843 from Russia), P. kuznetzovii (1941 described from Russia), P. chamissonis (1945 described from Sweden), and also P. nivea L. sensu Soják 1989, non Eriksen et al. 1999. North American and Greenland usage has focussed on P. arenosa and P. chamissonis, northwestern European usage on P. chamissonis, and Russian usage on P. arenosa, P. chamissonis, and P. kuznetzovii. The taxa are similar morphologically. There is close affinity across the North Atlantic, as emphasised by, e.g., Hultén (1945), and a similar close affinity occurs among plants on either side of the Bering Strait as emphasised by several authors. The major pattern is here interpreted as one widely Amphi-Atlantic entity and one widely Amphi-Beringian and American entity.
The name 'chamissonis' relates to the North Atlantic entity and probably also the name 'kuznetzovii', whereas the names 'arenosa' and 'nivea' sensu Soják relate to the amphi-Beringian plants. The name 'hookeriana', previously applied to the almost circumpolar species, most probably belongs to a more local entity, perhaps a hybrid, in Rocky Mountains (according to independent evaluations by J. Soják / B. Yurtsev and by B. Eriksen). The name 'nipharga' is much more enigmatic. It is currently applied to a plant of arctic northeastern Canada and Greenland, strongly resembling P. arenosa s.s., but differing in the hairs of the petioles. Potentilla arenosa s.s. has a characteristic combination of stiff, long, verrucose hairs and an understory of very short, stiff hairs. The understory on the petioles of P. nipharga consists of short, curved hairs. Another problem is that the name P. nipharga is typified on plants from northwestern Canada (Fort Good Hope on the Mackenzie River, leg. I.S. Onion, type in NY), outside the range where the entity currently is accepted. Soják and Russian authors (e.g., Yurtsev) consider P. nipharga as specifically different from P. arenosa. If they are merged, P. nipharga Rydb., 1908, has priority before P. arenosa (Turcz.) Juz. 1941.
The two main geographical entities are connected by specimens that appear to be morphologically intermediate both in North America, Greenland, and northern Eurasia. They are therefore better treated as subspecies than as species, as was done by Hultén (1968b). However, as the name has not yet been published for subsp. chamissonis, in this Flora we treat them as species.
Illustrations. • Close-up of plant. Plant with leaves that are green on the upper surface and white tomentose on the lower surface. Note the trifoliate leaf (black arrow) that has deeply dissected margins and a short-stipitate terminal leaflet. Ellesmere Island, Slidre River. CAN 533020. • Close-up of plant. Entire plant with caudex covered by leaf remains and tap-root. Note comparatively large petals and narrow sepals and episepals. Victoria Island, Burns Lake, 70°N, 110°W. CAN 533020. • Close-up of plant. Close-up of plant. Alaska, Umiat. July 5, 1961. CMN Photo library S78–632. • 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..