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 pulchella R. Br.

English: Branching cinquefoil,

French: Potentille jolie.

Rosaceae, Rose family.

Published in Chlor. Melvill. 19. 1823.

Type: Canada, Melville Island, Mr.(Rev. G) Fisher on W.E. Parry's first voyage 1819–1820.

Synonymy. Potentilla pulchella R.Br. var. elatior Lange, Consp. Fl. Groenland 4. 1880.

Potentilla pulchella R. Br. var. gracilicaulis A.E. Porsild, Sargentia, 4: 48. 1943.

Potentilla pulchella R. Br. subsp. gracilicaulis (A.E. Porsild) Jurtz., Byull. Moskovsk. Obshch. sp. Prir., Biol. 94, 3: 86. 1989.

?Potentilla keilhaui Sommerfelt, Mag. f. Naturvid. 2(1): 244. 1832.

Vegetative morphology. Plants (1–)3–20(–25) cm high; perennial herbs; caespitose. Taproot present (very stout). Ground level or underground stems vertical; 3–15 mm wide. Caudex present (short or long, with a leaf crown and lateral flowering branches (peduncles)). Aerial stems branching from a tap at or near ground level into two or more branches; covered by leaf bases. Leaves mainly basal; alternate; marcescent. Stipules present; 5–15(–20) mm long; 1–2(–2.5) mm wide; not sheathing; green; hairy (often pinkish when fresh, rusty reddish brown when marcescent); long-silky (more densely silky towards the apex); glandular; apex acuminate, or acute. Petioles (2–)5–40(–60) mm long; hairy; villous, or long-silky. Petiole hairs appressed and spreading; straight and crispate; smooth. Leaf blades compound. Blades 7–35(–50) mm long, 5–25(–30) mm wide, veins palmate (leaflet veins pinnate). Blade adaxial surface with sessile glands, hairy (hairs sometimes sparse), hairs long-silky, hairs simple, hairs dense or moderately dense, 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, hairs appressed or spreading (somewhat). Blade margins deeply divided or dentate, with non-glandular hairs (which are very long and tufted at the apex), with (1–)2–5 teeth on each side of the blade, with teeth all around the blade; degree of incision 50–90% (usually); apices obtuse, or rounded. Leaflet arrangement pinnate (with a large apical leaflet and basally smaller lateral leaflets, all leaflets usually deeply lacerate). Leaflets (3–)5(–7); 3–25(–30) mm long; 2–15(–25) mm wide; elliptic, or obovate; veins conspicuous. Apical leaflet base distinctly stipitate, or not distinctly stipitate; stipe 0–2(–4) mm long.

Reproductive morphology. Plants bisexual, or agamospermic (possibly). Flowering stems two or more per plant; shorter than the leaves, or about as high as the leaves, or conspicuously taller than the leaves; with leaves. Flowering stems hairy. Flowering stems tomentose and villous (sometimes silky). 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, or solitary (rarely). Inflorescences cymose; dense, or diffuse. Pedicels absent, or present. Flowers per inflorescence 1–3(–5); small, or medium-sized (smaller than most arctic Potentilla). Sepals conventional. Epicalyx present. Epicalyx segments (2–)3–4(–5) mm long. Epicalyx segments (0.8–)1–1.5(–1.8) mm wide. Epicalyx segments shorter than the calyx segments, or equal in length to the calyx segments. Epicalyx segments narrower than the calyx segments. Sepals 5; free; (0.8–)1–1.4(–1.6) mm long; (2–)3–5(–6) mm wide; green; accrescent. Calyx with sessile glands; hairy. Calyx hairs pilose, or long-silky; white or translucent. Calyx margins without cilia. Petals conventional; free; same length as the calyx, or longer than the calyx; 5; yellow (pale yellow, paler than most other other arctic potentillas); without contrasting markings; elliptic, or ovate; unlobed, or slightly lobed or undulating (very shallowly notched); 2–4(–7) mm long; 1–3(–5) mm wide. Stamens 20–30; stamen filaments glabrous. Anthers yellow; ellipsoid, or triangular; 0.2–0.3 mm long. Ovary superior; carpels 30–40; apocarpous. Styles 0.6–0.8 mm long; conical (narrowly conical); basal portion covered with long papillae, 0.1 mm high or higher, or 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; 0.5–0.8 mm long; 0.2–0.5 mm wide; glabrous; surface appearing veinless; indehiscent.

Chromosome information. 2n = 28.

2n (4x) = 28. Flovik (1940, Svalbard); Erlandsson (1942b); Holmen (1952, Greenland); Dansereau and Steiner (1956, northeastern Canada); Jørgensen et al. (1958, Greenland); Zhukova (1966, 1968, northeastern Asia); Mosquin and Hayley (1966, northern Canada); Packer and McPherson (1974, northern Alaska); Petrovsky and Zhukova (1981, Wrangel Island); Löve and Löve (1982a, Arctic Canada); Zhukova and Petrovsky (1985b, northern and northeastern Asia). Supposed basic chromosome number of family 7.

Ploidy levels recorded 4x.

Ecology and habitat. Elevation 1–300 m. Substrates: river terraces, ridges, cliffs, dry meadows, barrens (dry exposed clay and gravel slopes, sometimes barrens near the coast); imperfectly drained moist areas (occasionally, e.g., DAO 137500), solifluction slopes, dry, moderately well-drained areas; rocks, gravel, sand (commonly), silt, clay; with low organic content; calcareous, or nitrophilous. Plants thrive on dry, wind-swept and fine-grained ridges on calcareous substrates but also found in cliffs, screes, and on silty terraces and flats close to the coasts. The flowers are much smaller than in the other species and may be partly self-pollinated.

North American distribution. Alaska, Yukon, Northwest Territories Islands, continental Northwest Territories, Nunavut Islands, continental Nunavut, northern Quebec, Labrador, Newfoundland. Range in the Canadian Arctic Archipelago widespread. Common. Arctic. Arctic islands: Baffin, Devon, Ellesmere, Axel Heiberg, Parry islands (Bathurst, Eglinton, Melville and Prince Patrick), Banks, Victoria, Prince of Wales, Somerset, King William, Southampton, Coats (Nottingham and Salisbury).

Northern hemisphere distribution. Circumpolar. Svalbard – Franz Joseph Land, Polar Ural – Novaya Zemlya, Taimyr – Severnaya Zemlya, Anabar–Olenyok, Kharaulakh, Yana–Kolyma, Wrangel Island, West Alaska, North Alaska – Yukon, Central Canada, Labrador – Hudson Bay, Ellesmere Land – Peary Land, West Greenland, East Greenland.

General notes. Interruptedly circumpolar, almost exclusively in the Arctic but with many gaps, especially in Russia-Siberia. The gaps are probably a result of the species' strong affinity for dry and distinctly basic substrates.

Potentilla pulchella is fairly unambiguous in an arctic context and might be seen as a comparatively homogeneous arctic counterpart of the much more diverse boreal-temperate P. multifida L. complex (including P. bimundorum Soják and P. virgulata Nels.) that does not reach the Arctic islands.

Variety gracilicaulis A.E. Porsild was described to encompass more southern and western plants and was said to differ from the 'main' race (described from Melville Island) in being taller and with less hairy leaves. It was typified from Canada: Atkinson Pt., 01.-03.08.1927, leg. A.E.Porsild and R.T.Porsild 3632 (CAN) holotype. There is a wide range in size and indumentum in this species. Very tall plants are commonly found in manured sites, and populations of sub-glabrous plants are sometimes found in exposed coastal situations like shore terraces. A test of three such 'morphs' from Svalbard found that each of them kept some of the same appearance in cultivation but were inseparable in genetic markers (isozymes and RAPDs) (Hansen et al. 2000, Hamre 2000). Most of the numerous isoenzyme multiloci phenotypes were found in all three 'morphs', and they were interpreted as phenetic responses. Variety gracilicaulis might be one or more of such phenetic 'morphs' and thereby not worth recognition as a variety.

There is a geographical pattern in the variation in North America that might merit further analysis. In addition to the western 'gracilicaulis' plants, a conspicuously robust and hairy entity occurs in the Hudson Bay region. Other recognisable patterns are found in other regions outside North America. At present (2005), we proposed to keep this widespread and variable species as one entity throughout the circumpolar area.

Illustrations. • Habitat. Plants growing on slumping bank above beach. N.W.T., Banks Island, Sachs Harbour. 25 July, 1981. J.M. Gillett 18826. • Close-up of dwarf plant. Dwarf plant growing in cracks in calcareous loam on upper beach. Norway, Svalbard, Gipsdalen. August, 1997. Photograph by R. Elven. • Close-up of plant. Small compact dwarf plant with a small compact caudex area above the taproot, and silver gray leaves that are densely pubescent on both surfaces. Note the small flowers and the narrow and non-overlapping petals which are only slightly longer than sepals. Nunavut, Jenny Lind Island. CAN 273670. • Close-up of relatively large plant. The caudex zone is compact above the taproot. The pinnate leaves have five (or more) deeply dissected leaflets that are densely hairy and grey-silky on both surfaces. Stems elongate after anthesis. Nunavut, Baffin Island, Clyde Inlet. CAN 204925. • Close-up of plant. Mature plant with well-developed and branching caudex belowground, and much less biomass above ground. The caudex zone is well-developed above the taproot. Nunavut, Axel Heiberg Island. CAN 331246. • Close-up of plant. Drawing by Mrs. S. Bergh and Mrs. L. Barstad based on a collection from Svalbard, Dickson Land, Dickson Bay, Nathorst dal. 12 August, 1924. J. Lid. 0 203159. With permission of the Botanical Museum, University of Oslo, Norway. • Close-up of leaf. Mature leaf showing pinnate arrangement of leaflets with deeply dissected margins. Nunavut, Baffin Island, Clyde Inlet. CAN 204925. • Close-up of leaf base. Bases of mature leaves showing well-developed reddish stipules, and young gray-green stipules. Nunavut, Baffin Island, Clyde Inlet. CAN 204925. • Close-up of flower bud. Flower buds covered with long pilose or silky hairs. Manitoba, Churchill. Aiken and Brysting 01–037. CAN. • Close-up of flower bud. Bud covered with long silky hairs. Manitoba, Churchill. Aiken and Brysting 01–037. CAN. • Close-up of plant. The pinnate leaves usually have 5–7 oblanceolate leaflets with margins that are deeply divided into linear-lanceolate teeth. The lower surface of the leaves is densely covered by long soft, silky-white (smooth) hairs and appears silvery-grey. The upper surface of the leaves is usually silvery also but is sometimes subglabrous. The petals are entire (not notched). N.W.T., Banks Island, Aulavik National Park. 7 July, 1999. Aiken 99–022. CAN. • Close-up of plant. Flower with small, well-separated petals, that are barely longer than the sepals and are entire (not notched). Note the ring of stamens and the apocarpous gynoecium. Leaves with distinct tufts of hairs at the tip of each tooth. N.W.T., Banks Island, Aulavik National Park. 7 July, 1999. Aiken 99–022. CAN. • Close-up of flower. Post-anthesis flower with entire yellow petals, anthers withered or missing. Tips of some styles are blackish at this early stage of fruiting. N.W.T., Banks Island, Aulavik National Park. 1 July, 1999. Aiken 99–008. CAN. • Habitat. Dwarf plants growing in the shelter of a large rock on a silty upper beach flat. Norway, Svalbard, Gipsvika. July, 1997. Voucher at 0. Photograph by R. Elven. • Habitat. Very small plants in crevices of temporarily wet clay. Upper beach. Norway, Svalbard, Gipsvika. August, 1997. Voucher at 0. Photograph by R. Elven. • 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.