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

Potentilla vahliana Lehm.

Rosaceae, Rose family.

Published in Monogr. Potentill. 172. 1820.

Type: Described from Greenland.

Synonymy. Based on Potentilla hirsuta Vahl ex Hornem., Fl. Dan. 8, 22: t. 1390. 1810. Non Michx., Fl. Bor.-Amer. 1: 303. 1803.

Potentilla subvahliana auct., non Jurtz., Fl. Arct. URSS 9, 1: 319, 194. 1984.

Vegetative morphology. Plants (1–)2.5–10(–15) cm high; perennial herbs; caespitose. Taproot present (very stout). Ground level or underground stems vertical; 5–10(–15) mm wide. Caudex present (most often elongated with a build-up of macescent leaf remains). Aerial stems branching from a tap at or near ground level into two or more branches. Leaves mainly basal; alternate; dying annually and non-persistent (blades), or marcescent (petioles). Stipules present; (5–)6–9(–10) mm long; 1.5–2.5 mm wide; not sheathing; green (pinkish when fresh, reddish brown when marcescent); hairy; villous and long-silky; glandular; apex acute. Petioles (3–)5–10(–20) mm long; with sessile glands (mostly hidden by hairs); hairy; villous, or long-silky. Petiole hairs spreading; straight, wavy, and crispate; smooth. Leaf blades compound. Blades (6–)10–15(–20) mm long, (12–)15–25(–30) mm wide, veins palmate (leaflet veins pinnate). Blade adaxial surface with sessile glands, hairy, hairs villous or long-silky, hairs simple, hairs sparse 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 a mixture of white and yellow (or greyish hairs, a difference from P. uniflora and the P. nivea group), hairs straight or wavy, hairs appressed (the tomentose hairs) or spreading (the pilose hairs). Blade margins dentate, with non-glandular hairs, with 1–3(–4) teeth on each side of the blade, with teeth all around the blade or toward the apex; degree of incision 25–50(–75)%; apices rounded. Leaflet arrangement palmate. Leaflets 3; (8–)10–12(–15) mm long; (7–)8–12(–14) mm wide; obovate, or obtriangular; veins conspicuous. Apical leaflet base not distinctly stipitate.

Reproductive morphology. Plants bisexual, or agamospermic (possibly). Flowering stems two or more per plant; about as high as the leaves, or conspicuously taller than the leaves; with leaves. Flowering stems hairy. Flowering stems villous, tomentose, and long-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 solitary, or in inflorescences (more rarely). Inflorescences cymose (if applicable); lateral (on caudex); diffuse. Pedicels present (if applicable). Flowers per inflorescence 1(–4); medium-sized, or large. Sepals conventional. Epicalyx present. Epicalyx segments 3–5 mm long. Epicalyx segments 1.5–2.5 mm wide. Epicalyx segments equal in length to the calyx segments (approximately). Epicalyx segments narrower than the calyx segments, or equal in width to the calyx segments. Sepals 5; free; 2–3 mm long; 4–6(–8) mm wide; green; 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 (deep yellow); with contrasting markings (a dark orange base); obovate (obcordate and overlapping); slightly lobed or undulating; (6–)7–9(–10) mm long; (6–)7–9(–12) mm wide. Stamens 20–30 (numerous); stamen filaments glabrous. Anthers yellow; ellipsoid, or triangular; 0.3–0.5 mm long. Ovary superior; carpels 30–45; apocarpous. Styles 0.5–0.7 mm long; straight; basal portion covered with short papillae, less than 0.1 mm high. Ovules per ovary 1. Fruit with calyx persisting; dry; an aggregate of achenes; ovoid; green at maturity, or straw-coloured; 1.2–1.6 mm long; 0.6–1 mm wide; glabrous; surface venation reticulate, or appearing veinless; indehiscent.

Chromosome information. 2n = 42.

2n (6x) = 42/49/56. Jørgensen et al. (1958, Greenland);

2n (7x) = 49. Dansereau and Steiner (1956, northeastern Canada);

2n (8x) = 56. Dansereau and Steiner (1956, eastern Canada). Supposed basic chromosome number of family 7.

Ploidy levels recorded 6x.

Ecology and habitat. Substrates: river terraces, slopes (occasional on steep rocky south-facing slopes, (DAO Parmelee 3798)), ridges, cliffs, dry meadows, barrens (commonly found in exposed sites that support little vegetation); dry; rocks, gravel, sand, silt (rarely), clay (rarely); with low organic content; acidic, or calcareous, or nitrophilous (rarely), or non-calcareous. Dry, wind-swept ridges and cliffs, always in sites with little or no snow in winter, and mainly on calcareous substrates. This large-flowered species is most probably insect-pollinated regularly, and its morphological variation pattern, with small regional variation, might indicate a fair level of sexual outcrossing.

North American distribution. The Yukon Territory record from the mainland west of Mackenzie River (Herschel Island?) mapped by Porsild and Cody (1980) should be checked against P. uniflora as should the records from Alaska mapped by Hultén (1968b). These records might belong to P. subvahliana Jurtz., described from the northeastern Asian Wrangel Island and which might well occur in northwestern North America. Alaska (?, uncertain), Yukon (?, uncertain), Northwest Territories Islands, continental Northwest Territories, Nunavut Islands, continental Nunavut, northern Quebec. Range in the Canadian Arctic Archipelago widespread. Common. Arctic. Arctic islands: Baffin, Ellesmere, Axel Heiberg, Parry islands (Emerald, Melville, Prince Patrick), Banks, Victoria, Somerset, King William, Southampton (Melville Peninsula).

Northern hemisphere distribution. North American. West Alaska (?), North Alaska – Yukon (?), Central Canada, Labrador – Hudson Bay, Ellesmere Land – Peary Land, West Greenland.

General notes. Canadian plants that Yurtsev had identified as P. subvahliana were redetermined by Elven to P. vahliana in 2000, following a comparison with Greenland plants identified by Yurtsev as P. vahliana s.s. The single specimen annotated as P. subvahliana by Soják in CAN and DAO is a P. uniflora hybrid with P. arenosa (probably a F1 hybrid). The western limit of the distribution in the arctic islands of P. vahliana seems to be Banks and Victoria. Reports from northern Alaska (Hultén 1968b) are not confirmed, and no specimens of P. vahliana from the northern Yukon or northern Alaska have been found in CAN or DAO. There might be a (slightly) different plant (a low-ploidal entity) on the west side of the Bering Straits, justifying the recognition of P. subvahliana Jurtz., but further study is needed on the differences between P. vahliana and P. subvahliana. Thus, the name P. vahliana is applied for the Canadian plants.

Sometimes the differences between P. vahliana and P. uniflora are slight. Some specimens from continental North America eastwards from the Mackenzie River seem to combine characters and are difficult to assign with certainty. Treating members of this aggregate as subspecies might be more appropriate, but as ploidy level differences are reported (Löve and Löve 1975), they are currently treated as species.

Illustrations. • Habitat. Plant on gravel ridge. N.W.T., Banks Island, Parker River valley. August, 1999. Voucher at 0. Photograph by R. Elven. • Habitat. Plants growing on a dry slope among rocks. Nunavut, Southampton Island, Coral Harbour. Aiken and Brysting 01–068. CAN. • Close-up of plant. Small and compact plant with well-developed, elongated and branching underground caudex that is tightly covered with leaf bases, the marcescent remains of previous season's leaves and a small compact tuft of current season's leaves. Stems are usually one-flowered. Calyx and epicalyx segments are similar in width. N.W.T., Victoria Island, Holman. CAN 518390. • Close-up of plant. Larger plant with well-developed underground caudex and a solitary large flower. Plant with trifoliate leaves, each leaflet with only 3–5 triangular teeth. Leaf upper surface often green, sometimes densely hairy. Leaf lower surface with a yellowish grey (not a silvery) indumentum. N.W.T., Melville Island, Ibbett Bay. CAN 495870. • Close-up of flowers. Flowers approximately 1 cm in diameter. Note the often overlapping heart-shaped petals are orange towards the centre. Nunavut, Southampton Island, Coral Harbour. Aiken and Brysting 01–068. CAN. • Close-up of flowers. Epicalyx and calyx are shorter than the heart-shaped petals that are darker orange towards the centre. Numerous pre-anthesis anthers sometimes have a dark brown spot on the tip. Young, paler yellow carpels are developing in the centre of the flower. Aiken and Brysting 01–068. CAN. • 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.

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