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

Petasites frigidus (L.) Fr. s.l.

English: Sweet coltsfoot, arrowleaf sweet soltsfoot,

French: Pétasite palmé.

Asteraceae (Compositae), Daisy family.

Published in Summa Veg. Scand. 1: 182. 1845.

Type: Described from European mountains and Siberia: "Alpium Lapponiæ, Helvetiæ, Sibiriæ". The central European plants are now assigned to another species.

Synonymy. Tussilago frigida L., Sp. Pl. 2: 865. 1753.

Nardosmia frigida (L.) Hooker, Fl. Bor.-Amer., Hooker, 1: 307. 1833.

Petasites frigidus (L.) Fr. subsp. arcticus (A.E. Porsild) Cody, Can. Field-Natural. 108: 94.1994.

Petasites arcticus A.E. Porsild, Sargentia 4: 74. 1943.

Petasites frigidus (L.) Fr. subsp. nivalis (Greene) Cody, Can. Field-Natural. 108: 94. 1994.

Petasites nivalis Greene, Pittonia 2: 18. 1889.

Petasites hyperboreus Rydberg, N. Amer. Fl. 34: 312. 1927.

Nardosmia arctica (A.E. Porsild) Á. Löve and D. Löve, Bot. Not. 128: 519. 1976. Type from Mackenzie River delta, East Branch, CAN, see Porsild, 74. 1943.

Vegetative morphology. Plants (10–)15–35 cm high; perennial herbs. Only fibrous roots present. Roots pallid-brown (pale). Ground level or underground stems horizontal, or vertical; rhizomatous, or stoloniferous; elongate (usually), or compact; 2–5 mm wide. Ground level or underground stems scales present (often with a prominent expanded base and entire, unlobed margins); 2–7 (lower scale leaves alternate, uppermost scale leaves opposite or almost so when they are present). Caudex absent. Aerial stems erect. Leaves present; heterophyllous (lanceolate, with unlobed margins on flowering stems early season; vegetative leaves deltoid with lobed margins); mainly basal (vegetative leaves that may develop after flowering), or distributed along the stems (on rhizomes or flowering stems); alternate; dying annually and non-persistent. Petioles present (late season leaves), or absent (early season leaves); 0–100 mm long; winged (sometimes expanded and sheathing at the base), or not winged (most of the length); glabrous, or hairy (sparsely); woolly (if applicable). Petiole hairs shorter than the diameter of the petiole; appressed, or spreading; floccose; smooth. Leaf blades simple. Leaf blade bases cordate (vegetative leaves), or truncate (flowering stem leaves). Blades (5–)10–70 mm long, (5–)10–70 mm wide, spreading, linear (flowering stem leaves) or triangular (deltoid, vegetative leaves), flat, veins pinnate. Blade adaxial surface with sessile glands or without sessile glands, glabrous. Blade abaxial surface hairy, hairs woolly, hairs very dense, hairs white, hairs wavy, hairs appressed. Blades lobed. Blade margins entire (flowering stem leaves) or dentate (occasionally on the lobes of vegetative leaves), glabrous, with teeth per cm 1–3; degree of incision 5–10%; apices acute.

Reproductive morphology. Flowering stems solitary; with leaves. Flowering stem hairs simple; shorter than the diameter of the flowering stem; white or translucent. Inflorescences of several flowering heads; terminal, or lateral; 2.5–10 cm long; 20–70 mm wide. Flowering heads 8–15 mm deep; 8–12 mm wide; with disc and ray florets. Pedicels subtending flowering heads; with non-glandular hairs. Involucral bracts present. Number of rows 1–2. Outer involucral bracts mostly green; lying adjacent to the flowers; linear, or lanceolate; 6.5–7 mm high; 0.9–1.1 mm wide; sparsely hairy; without glandular hairs. Inner involucral bracts 6.5–7 mm high; 1–1.5 mm wide (broader than the outer bracts); margins narrow and scarious, less than one quarter of the bract; apex entire. Flowers radially symmetrical (actinomorphic) (disc florets), or bilaterally symmetrical (zygomorphic) (ray florets); unisexual, or bisexual. Sepals represented by a pappus. Pappus with a single row of hairs; yellowish, or whitish. Ray florets pappus 7–9 mm long. Disc florets pappus 8–10 mm long. Petals conventional; fused; 5; white, or red (deep red wine colour), or pink; 7.5–9 mm long. Corolla flat, strap-like (ray florets), or tubular, or funnel-form (disc florets); 5-lobed (disc florets). Ray florets limb 8–9 mm long; 1.5–3 mm wide. Stamens 5. Anthers 2–2.4 mm long. Ovary inferior; carpels 2; syncarpous. Styles 1; 10–12 mm long. Stigmas per ovary 2. Placentation basal. Ovules per ovary 1. Fruit sessile; with calyx persisting (as a pappus that has elongated to be 12–14 mm long); dry; cypselas (no evidence of fruit set in Arctic Island specimens at CAN); indehiscent. Seeds 1.

Chromosome information. 2n = 60, or 80, or 90.

2n (6x) = 60. Flovik (1940); Sokolovskaya and Strelkova (1941, northern Russia; Kolguev, 1960); Zhukova (1956a, eastern Chukotka; 1965b, Wrangel Island; 1980, southern Chukotka; 1982, northeastern Asia); Mosquin and Hayley (1966, northern Canada); Knaben and Engelskjøn (1967, Norway); Johnson and Packer (1968, northwestern Alaska); Laane (1969b, Norway); Suda, in Löve (1969, northern Canada);

2n = about 60. Sokolovskaya (1970, northeastern Russia); Zhukova and Tikhonova (1971, Chukotka; 1973, Chukotka); Zhukova et al. (1973, 1977, north to northeastern Asia); Packer and McPherson (1974, northern Alaska); Belaeva and Siplivinsky (1975, southern and northern Siberia); Krogulevich (1976a and b, southern and northern Siberia, 1978); Krogulevich and Rostovtseva (1984, Siberia); Engelskjøn (1979, Norway); Malachova et al. (1979, Siberia); Petrovsky and Zhukova (1981, Wrangel Island); Zhukova and Petrovsky (1987b, north and northeastern Asia); Lavrenko et al. (1989, 1990, northern Russia); Lavrenko and Serditov (1991, northern Russia);

2n (8x) = 80. Zhukova and Petrovsky (1976, western Chukotka);

2n (6x) 60. Sørensen and Christiansen (1964); Sokolovskaya (1966, northeastern Asia, 2n = about 60); Löve and Löve (1975, 1982a, central Canada); Morton (1981); Packer and Witkus (in Á. Löve 1982b, western Canada) for Petasites frigidus (L.) Fr. subsp. palmatus (Aiton) Cody (1994); Taylor and Brockman (1966, western Canada); Mulligan (1969, Alaska);

2n (9x) = 90. Packer and McPherson (1974, northern Alaska).

Ploidy levels recorded 6x and 9x.

Indigenous knowledge. Anderson (1939) noted that the leaves were gathered as greens, but to a limited extent in Alaska at that time.

Kjellman (1982) claimed that this plant is a favourite of the Chukchi, who use the mature leaves to prepare a very special variety of "sauerkraut".

Porsild (1957) indicated that the young leaves and flowering stems may be eaten raw as salad or cooked as a potherb. Schofield (1989) and Heller (1985) mentioned that the leaves and flowering stems were used as a food in Alaska and Siberia by local Eskimo groups.

The leaves have been used by herbalists to make a cough syrup, which is often flavoured with honey. It is said to relieve persistent coughs, bronchial congestions, and asthma (Burt 2000). This author found no evidence that the Inuit in the central arctic use this plant.

Ecology and habitat. Substrates: along streams, river terraces; imperfectly drained moist areas, seepage slopes; gravel, sand, silt, moss; with high organic content. Moist organic sand over gravel, steep talus slopes (CAN 128166); sedge area adjacent to gabbroic outcrop.

North American distribution. Alaska, Yukon, Northwest Territories Islands, continental Northwest Territories, Nunavut Islands, continental Nunavut, Labrador, Newfoundland (as var. or subsp. palmatus in Labrador and Newfoundland). Range in the Canadian Arctic Archipelago limited. Uncommon. Low Arctic. Arctic islands: Parry islands (Melville, Prince Patrick), Banks, Victoria.

Northern hemisphere distribution. Circumpolar, or circumboreal (with a gap between Greenland and northeastern Canada). Northern Fennoscandian, 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.

General notes. Elven et al. (2003) noted that "Löve and Löve (1975) splitted Petasites s.l. [into] three genera. Petasites s.s. and Nardosmia, both with x = 10, were separated on morphological criteria from each other. Endocellion, with x = 7, was separated on both morphological and cytological criteria from the others. As for Petasites and Nardosmia, hybridisation with production of 'hybridogenous species' is reported between species assigned to the two genera by the Löves (P. palmatus × P. sagittatus = P. vitifolius); see Bogle (Rhodora 70: 533–551. 1968)."

According to Cody (1996), a local endemic occurs in the Richardson and Mackenzie Mountains in northwestern Canada and reaches the Arctic both on the coast and in the northern Richardson Mountains. Cody recognised this entity as Petasites frigidus (L.) Fr. subsp. arcticus (A.E. Porsild) Cody, in Can. Field-Nat. 108: 94. 1994. Type from Mackenzie River delta, East Branch, CAN (see Porsild 1943: 74).

Petasites frigidus (L.) Fr. subsp. nivalis (Greene) Cody (Can. Field-Nat. 108: 94. 1994) is intermediate in some aspects between subsp. frigidus and subsp. palmatus but occupies a range of its own in northwestern America, west and partly north of subsp. palmatus.

Cherniawsky and Bayer (1998a) considered Petasites a taxonomically difficult genus in North America and presented a table comparing systematic treatments of the genus by Rydberg (1927), Cronquist (1978), Hultén (1950), Bogle (1968), Scoggan (1979), Porsild and Cody (1980), and Packer (1983). Cherniawsky and Bayer (1998b) stated that individuals are polygamodioecious, perennial, and clonal herbs that are widely distributed across Canada, Alaska, and the northern contiguous United States as far south as California. All North American taxa of Petasites have sympatric ranges. These authors concluded that the morphological differentiation between P. sagittatus and other taxa of Petasites is not considered sufficient to warrant recognition of specific status. They recommended that only one polymorphic species of Petasites in North America be recognised (P. frigidus with three varieties) in addition to one hybrid taxon originating from a cross between two of the varieties.

Korobkov (in Elven et al. (2003)) proposed four species in the P. frigidus aggregate: P. frigidus s.s., P. hyperboreus Rydberg, P. palmatus (Ait.) A. Gray, and P. arcticus A.E. Porsild. In North America where most of the variation occurs these intergrade and it is often impossible to keep them as species and perhaps difficult even as subspecies. Bayer et al (2006) treat them as varieties. Pending further information on the subspecific nomenclature, in the present treatment we are using the name of the species P. frigidus s.l.

Illustrations. • Habitat. Plants between the markers growing in a wet seepage crack with moss and Eriophorum. N.W.T., Banks Island, Aulavik National Park. Aiken 99–013. CAN. Scale bar in cm. • Young inflorescence. Inflorescence in bud, subsp. frigidus. Norway, Troms, Tromsoe, Floya. 24 June, 1979. Photograph by R. Elven. • Close-up of plants. Plants with flowerings heads in bud. Note the short, stout, flowering stem and the lobed, young vegetative leaves that are unfolding. Aiken 99–013. CAN. • Close-up of inflorescence. Inflorescence with a few almost white ray florets, a few open, pale pink disc florets, and disc flower buds that are red on what will be the underside of the petals when the flower opens. N.W.T., Banks Island, Aulavik National Park. 2 July, 1999. Aiken 99–013. CAN. • Close-up of inflorescence. Three capitula with pale ray florets expanded and disc florets beginning to open. N.W.T., Banks Island, Aulavik National Park, 73°48'N, 119°52'W. 2 July, 1999. Aiken 99–013. CAN. • Close-up of inflorescence. Flowering head with disc florets in bud and beginning to open, rings of deep pink anthers in some flowers and fuzzy, pale pinkish, tuning-fork shaped stigmas in others. N.W.T., Banks Island, Aulavik National Park. 11 July, 1999. Aiken 99–061. CAN. • Close-up of inflorescence. Inflorescence in flower with disc florets open showing petals with acute reflexed tips, and long styles tipped with velcro-like stigmas to trap pollen. N.W.T., Banks Island, Aulavik National Park. 11 July, 1999. Aiken 99–061. CAN. • Plants setting seed. Flowering heads setting seed, covered with white pappus hairs that are on the cypselas. Note deltoid basal leaves. Plants growing in birch-empetrum tundra. N.W.T., Tuktoyaktuk. 20 July, 1981. J.M. Gillett 18696. CAN. • Inflorescence in seed. Fruiting inflorescence (capulescence) with expanded pom poms of white pappus hairs, and younger flowering heads that have not expanded. Small leaves on the flowering stems and large, lobed basal deltoid leaves. N.W.T. Tuktoyaktuk. 20 July, 1981. J.M. Gillett 18696. CAN. • Black and white drawing. Drawing by Mrs. S. Bergh and Mrs. L. Barstad based on a collection from Svalbard, Nordenskiöld Land, Advent Bay, Torvedalen, austsida. 23 Juluy, 1924. J. Lid. O 201324. With permission of the Botanical Museum, University of Oslo, Norway. • 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.