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 hyparctica Malte s.l.

English: Arctic cinquefoil,

French: Potentille subartique.

Rosaceae, Rose family.

Published in Rhodora 36: 177. 1934.

Type: Canada: Ellesmere Land, Craig Harbour, 76°12'N, 81°20'W, 2 Aug. 1927, leg. M.O. Malte. Holotype: CAN! "Fragment of holotype": S!


Potentilla emarginata sensu Pursh 1814, non Desf. 1804.

?Potentilla robbinsiana Oakes, in Torrey and A.Gray, Fl. N. Amer. 1: 441. 1840.

?Potentilla hyparctica Malte subsp. robbinsiana (Oakes) Á. Löve and D. Löve, Taxon 13: 204. 1964.

Potentilla groenlandica R.Br., nom. nud., Voy. Explor. Baffin's Bay, App., ed. 2, 2: 193. 1819. (The name may have been validated by Malte.)

Vegetative morphology. Plants (1–)5–15(–20) cm high; perennial herbs; caespitose. Taproot present (comparatively slender to stout). Ground level or underground stems vertical; 3–12 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; 6–12 mm long; 1–5(–6) mm wide; green (first year, brownish red when marcescent); hairy; pilose; glandular; apex acute, or obtuse. Petioles (5–)10–40(–60) mm long; with sessile glands (abundant or sparse); hairy; pilose. Petiole hairs longer than the diameter of the petiole; spreading, or erect; straight (mainly); smooth, or rough. Leaf blades compound. Blades (5–)8–30(–35) mm long, (8–)10–25(–30) mm wide, veins palmate (leaflet veins pinnate). Blade adaxial surface with sessile glands, glabrous or hairy, hairs pilose or long-silky, hairs simple, hairs sparse or moderately dense, hairs white, or translucent. Blade abaxial surface without sessile glands or glandular hairs, hairy, hairs pilose or long-silky, hairs white, hairs straight, hairs appressed or spreading. Blade margins crenate or dentate, with non-glandular hairs, with 1–5 teeth on each side of the blade, with teeth all around the blade or toward the apex; degree of incision (5–)25–60(–70)%; apices rounded. Leaflet arrangement palmate (very rarely digitate). Leaflets 3(–5); (4–)6–20(–22) mm long; (3–)5–15(–18) mm wide; elliptic, or ovate, or obovate, or obtriangular; veins conspicuous. Apical leaflet base distinctly stipitate, or not distinctly stipitate; stipe (0–)1–5(–7) mm long.

Reproductive morphology. Plants bisexual, or agamospermic. Flowering stems about as high as the leaves, or conspicuously taller than the leaves; with leaves. Flowering stems hairy. Flowering stems pilose, villous, and tomentose. 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. Inflorescences cymose (if applicable); lateral; diffuse. Flowers per inflorescence 1–2(–4); medium-sized, or large. Sepals conventional. Epicalyx present. Epicalyx segments 2.5–6 mm long. Epicalyx segments 1–3.5(–4) mm wide. Epicalyx segments shorter than the calyx segments, or equal in length to the calyx segments. Epicalyx segments narrower than the calyx segments, or equal in width to the calyx segments. Sepals 5; free; 2.2–3.5 mm long; 4–8 mm wide; green, or brown (reddish); accrescent. Calyx with sessile glands; hairy. Calyx hairs pilose; white or translucent. Calyx margins ciliate. Petals conventional; free; 5; yellow (very pale); with contrasting markings; obovate; slightly lobed or undulating; (4–)5–8(–10) mm long; (3.5–)4–8(–9) mm wide. Stamens 15–30; stamen filaments glabrous. Anthers yellow; ellipsoid, or triangular; 0.25–0.4 mm long. Ovary superior; carpels 30–45; apocarpous. Styles 0.6–0.8 mm long; basal portion smooth, or covered with short papillae, less than 0.1 mm high (very low papillae). Ovules per ovary 1. Fruit sessile; with calyx persisting; dry; an aggregate of achenes; ovoid; green at maturity, or straw-coloured; 0.9–1.5 mm long; 0.7–1.2 mm wide; surface venation reticulate, or appearing veinless; indehiscent.

Chromosome information. 2n = 28, 42, 49. For the collective species.

2n (4x) = 28. Zhukova et al. (1977, northeastern Asia); Zhukova and Petrovsky (1985b, northern and northeastern Asia);

2n (6x) = 42. Flovik (1940, Svalbard); Dansereau and Steiner (1956, northern Alaska); Jørgensen et al. (1958, Greenland); Zhukova (1965a, Chukotka, 1966, 1968, northeastern Asia); Mosquin and Hayley (1966, northern Canada, 2n = about 42); Hedberg (1967, northern Canada, 2n = about 42); Johnson and Packer (1968, northwestern Alaska); Packer and McPherson (1974, northern Alaska); Zhukova and Petrovsky (1976, western Chukotka, 1985b, north and northeastern Asia); Dawe and Murray in Löve (1979, Alaska, two counts); Engelskjøn (1979, Svalbard); Krogulevich (1984, Siberia); Dalgaard (1989, western Greenland);

2n (7x) = 49. Dansereau and Steiner (1956, northeastern Canada); Löve and Löve (1965, 1966b, northeastern USA, for P. robbinsiana s.s.). Supposed basic chromosome number of family 7.

Ploidy levels recorded 4x, 6x, 7x.

Ecology and habitat. Substrates: wet meadows, hummocks, snow patches, depressions of low-centre polygons, tundra, slopes, ridges, cliffs, dry meadows; imperfectly drained moist areas (rarely), seepage slopes, solifluction slopes, dry, moderately well-drained areas; rocks, gravel (DAO 211523, 612570), silt, clay; with low organic content, with high organic content, peat; acidic (mostly), or calcareous (DAO 211523, 612570), or nitrophilous, or non-calcareous. A slightly acidophilic species on ridges, hummocks, on solifluction slopes, and sometimes in snowbeds, often also found on bird hummocks. In acidic areas this is often the only species of Potentilla found. It is distinctly less frequent in, and sometimes absent from, larger limestone areas. It is very hardy and reaches the climatic Polar Desert areas, as do P. pulchella and P. vahliana, which are often found in different areas, owing to their different edaphic demands.

North American distribution. A circumpolar taxon very common in both the high and Low Arctic parts and often with isolated occurrences in temperate mountains. Alaska, Yukon, continental Northwest Territories, Nunavut Islands, continental Nunavut, northern Quebec, Labrador. Range in the Canadian Arctic Archipelago widespread (northern race), or limited (southern race). Common (northern race), uncommon (southern race). High Arctic (northern race), Low Arctic, boreal (southern race). Arctic islands: Baffin, Devon, Ellesmere, Axel Heiberg, Parry islands (Bathurst, Cameron, Eglington, Emerald, Mackenzie King, Melville, Prince Patrick), Banks, Somerset, Southampton, Coats (Amund and Ellef Ringnes, Meighen, Cornwall, Loughead, Bylot, Digges, Resolution and Salisbury islands).

Northern hemisphere distribution. Circumpolar (northern race), or North American (southern race). Kanin–Pechora, Svalbard – Franz Joseph Land, Polar Ural – Novaya Zemlya, Yamal–Gydan, Taimyr – Severnaya Zemlya, Anabar–Olenyok, Kharaulakh, Yana–Kolyma, West Chukotka, Wrangel Island, South Chukotka, East Chukotka, West Alaska, North Alaska – Yukon, Central Canada, Labrador – Hudson Bay, Ellesmere Land – Peary Land, West Greenland, East Greenland (northern race, or western and northern Alaska and central and southeastern Arctic Canada).

General notes. The long accepted name P. emarginata Pursh, 1814, has to be rejected, as it is a later homonym of P. emarginata Desv. 1804. The priority name at species level depends on whether or not the marginal populations in the temperate White Mountains (New Hampshire, P. robbinsiana Oakes) and/or those in the Aleutian and Commodore islands (P. nana Willd. ex Schltdl.) are included. Potentilla nana was described in 1813–1816 and is the oldest name in the group. Russian authors consider it as a distinct and separate species, but the matter is not closed. Potentilla robbinsiana was described in 1840, long before P. hyparctica Malte was described from Ellesmere Island. They were united with the arctic plants at species level (but treated as different subspecies) by Löve and Solbrig (1964) and Löve and Löve (1965). However, Hultén (1946) considered P. robbinsiana more closely related to the mainly Asian P. elegans Cham. and Schltdl. Pending a more thorough comparison between P. hyparctica, P. nana, and P. robbinsiana, the former name is retained for the arctic plants. A parallel alpine taxon in northeastern Asia has been described as P. pulviniformis Khokhr. Similar slightly deviating alpine plants, currently identified as P. hyparctica, are known from southern Alaska and Scandinavia.

The material from the Canadian Arctic falls into two fairly distinct entities, here only named Northern Race and Southern Race. The Northern Race contains the majority of the plants found throughout the Arctic islands except for southern Baffin and also on several of the northern mainland peninsulas. It has been named as P. groenlandica R. Br. The Southern Race contains the majority of plants that occur in southern Baffin Island, the islands in Hudson Bay (except for Southampton), and on the mainland from Alaska to Labrador. It has also been named as var. elatior (Abromeit) Fernald. The types behind these names have not yet been studied.

The two races differ fairly consistently; there seems to be comparatively little overlap in characters and distributions. They are, however, obviously closely related and should be considered as major geographical races, i.e., as subspecies rather than species. The two races differ in several morphological features, as seen from the descriptions. Northern Race plants are more slender, more hairy, with leaflets that are more dissected and with more acute lobes. They have much smaller and more acute calyx and epicalyx segments. All Ellesmere Island specimens from CAN and DAO belong to this 'majority' race, and the type specimen of P. hyparctica also belongs here. The Asian P. pulviniformis is very close to the Northern Race.

Southern Race plants are taller, have rounded leaflet lobes, and large and rounded epicalyx and calyx segments. As plants matching this description predominate on continental North America, it is at least probable that the type of P. robbinsiana could belong to the southern race, but this must be checked against the type.

Formal names for the races are not proposed here, mainly because the variation outside eastern Canada was not analysed. There might be relevant names also available from other regions.

The data for the two races were scored independently. When it was compared the following differences were noted.

Plant heights: southern race (2-)5–15(-20) cm, northern race, (1-)5–12(-15) cm

Stipule widths: southern race (2-)3–5(-6), northern race 1–2(-3) mm

Petiole lengths: southern race (10-)15–40(-60) mm, northern race (5-)10–20(-40) mm

Sessile glands on petioles: southern race sparse, northern race, abundant

Leaf blade lengths: southern race (5-)12–30(-35) mm, northern race (5-)8–15(-20) mm

Leaf blade widths: southern race (10-)12–25(-30) mm, northern race (8-)10–15(-20) mm

Leaflet blade lengths: southern race (5-)8–20(-22) mm, northern race (4-)6–12(-15) mm

Leaflet blade widths: southern race (4-)8–15(-18) mm, northern race (3-)5–8(-12) mm

Leaflet blade margins degree of incision: southern race 5–60%, northern race 25–75%

Apical leaflet: southern race maybe stipitate, northern race, not stipitate

Epicalyx segments lengths: southern race 3–6 mm, northern race 2.5–4 mm

Epicalyx segments widths: southern race 2–3.5(-4) mm, northern race 1–1.5 mm

Sepal lengths: southern race 6.5–8 mm, northern race 4–6(-8) mm

Sepal widths: southern race (2.8-)3–3.5 mm, northern race 2.2–3 mm

Petals widths: southern race (4-)5–8(-9) mm, northern race (3.5-)4–6(-7) mm

Fruit length: southern race 1.2–1.5 mm, northern race 0.9–1.2 mm

Fruit width: southern race 0.9–1.2 mm, northern race 0.7–1 mm

Distribution: southern race, not in N.W.T. islands, southern race not in Labrador and Quebec.

Illustrations. • Habitat: Baffin Island, Ogac Lake. Plant with yellow flowers growing at the base of a talus slope. Nunavut, Baffin Island, Ogac Lake. 10 July, 2004. Aiken and LeBlanc 04–039. CAN. • Habitat: Baffin Island, Ogac lake. Plants with yellow flowers growing in a snow patch area beside the lake. Nunavut, Baffin Island, Ogac Lake. 10 July, 2004. Aiken and LeBlanc 04–039. CAN 586508. • Habitat: Cape Dorset. Several plants in a sheltered and moist zone behind the guest house. Nunavut, Baffin Island, Cape Dorset. 3 August, 2005. Aiken. No voucher. • Side view of flower. Side view of flower showing epicalyx spreading at right angles to the petals and calyx erect and close to the petals. Nunavut, Baffin Island, Ogac Lake. 10 July, 2004. Aiken and LeBlanc 04–039. CAN 586508. • Hairs on stem and sepals. Note long-silky white or translucent straight hairs that are appressed on the flowering stem and spreading on the epicalyx and calyx segments. Aiken and LeBlanc 04–039. CAN 586508. • Flower with nectaries. Note characteristic orange flash at the base of the petals, several anthers in two rows, red nectaries in a whorl between the anthers and the apocarpous ovary with numerous stigmas. Aiken and LeBlanc 04–039. CAN 586508. • 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.