Flora of the Canadian Arctic Archipelago
English: One flower fleabane,
French: Vergerette à capitule laineux.
Asteraceae (Compositae), Daisy family.
Published in Brittonia 6: 236. 1947.
Type: Described from Greenland: "ad 200 pedes supra mare et prope rivulum ad Niakarnak Coloniae Umanak".
Synonymy. Erigeron eriocephalus J.Vahl in Hornem., Fl. Dan. 13, 39: 6, pl. 2299. 1840.
Erigeron uniflorus L. subsp. eriocephalus (J.Vahl) Cronquist, Brittonia 6: 236. 1947.
Erigeron uniflorus L. var. eriocephalus (J.Vahl) B. Boivin, Phytologia 23: 49. 1972.
Vegetative morphology. Plants 5–20(–25) cm high; perennial herbs. Taproot present, or only fibrous roots present (fibrous roots developed from the caudex). Ground level or underground stems vertical. Caudex present. Aerial stems erect. Leaves present; mainly basal; erect; alternate; dying annually and non-persistent. Petioles present (long tapering leaf blade bases, rather than true petioles), or absent (leaves on the flowering stems); 0–40 mm long; hairy; pilose. Petiole hairs shorter than the diameter of the petiole; spreading; straight, or curved (multicellular with up to 4(-5) cells). Leaf blade bases attenuate. Leaves not grass-like. Blades (10–)20–40(–65) mm long, 2–6 mm wide, spreading, obovate, flat, appearing single-veined. Blade adaxial surface glabrous or hairy, hairs pilose or villous (if applicable), hairs simple, hairs sparse, hairs white, or translucent or grey. Blade abaxial surface hairy, hairs pilose or villous, hairs sparse, hairs white, hairs straight or curved, hairs spreading or erect (only on the margins). Blade margins entire, with non-glandular hairs (that are often at right angles to the margins); apices obtuse, or rounded.
Reproductive morphology. Flowering stems solitary; conspicuously taller than the leaves (usually); with leaves. Flowering stems hairy. Flowering stems pilose. Flowering stem hairs simple; shorter than the diameter of the flowering stem; white or translucent. Inflorescences solitary heads; terminal. Flowering heads 10–15 mm deep; (10–)15–25 mm wide; with disc and ray florets. Involucral bracts present. Number of rows 1–2. Outer involucral bracts mostly wine red or purple pigmented; lying adjacent to the flowers; linear, or lanceolate; 5–12 mm high; 0.5–1.5 mm wide; densely hairy (especially on the margins); without glandular hairs. Inner involucral bracts lanceolate (narrowly); 7.5–8.5 mm high; 0.8–1 mm wide; margins narrow and scarious, less than one quarter of the bract. 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 (white), or whitish (pale yellow on drying). Ray florets pappus 3.5–4.5 mm long. Disc florets pappus 4–5 mm long. Petals conventional; fused; 5; white (when young), or purple (with age, disc florets with purple tips to the petals); 3–3.5 mm long. Corolla tubular, or funnel-form (disc florets), or flat, strap-like (ray florets); unlobed (disc florets; ray florets vaguely lobed). Ray florets 80–100; limb 6–8 mm long; limb 0.2–0.3 mm wide. Stamens absent (2–2.5 only empty shells). Ovary inferior; carpels 2; syncarpous. Styles 1; 2–5 mm long (2–3 mm long disc florets; 4–5 mm long ray florets). Stigmas per ovary 2. Placentation basal. Ovules per ovary 1. Fruit sessile; with calyx persisting; dry; cypselas; oblong; yellowish, or brown; 1.8–2.2 mm long; 0.4–0.6 mm wide; hairy; indehiscent. Seeds 1.
Chromosome information. 2n = 18.
2n (2x) = 18. Holmgren (1919, northern Europe); Löve (1950, Iceland); Löve and Löve (1956, Iceland); Jørgensen et al. (1958, Greenland); Mosquin and Hayley (1966, northern Canada); Hedberg (1967, northern Canada); Zhukova et al. (1973, 1977, northeastern Asia); Zhukova and Petrovsky (1975, 1976, western Chukotka).
Ploidy levels recorded 2x.
Ecology and habitat. Substrates: river terraces, slopes; moderately well-drained areas; sand, silt, till; with low organic content, with high organic content, peat; calcareous, or nitrophilous. Well-drained sand and silt; dry calcareous sandy knoll; basalt talus, silt plain near an eroding peat bluff; partially eroded, low-centre polygons; snow beds; disturbed gravel and boulders rich with organics (CAN 526676); shale slope; plate-like gravel, weathered from black calcareous shale formation (CAN 489896); sparse in moss (CAN 393641); alkaline limestone and mud talus rubble; rocky stream bed (CAN 483738); among boulders; occasional on stony screes; growing on major peat deposit and silt in old lake bed (CAN 485350). This information from herbarium labels supplements the comment by Porsild (1957): 'in moist, grassy places, often growing in herbmats below perennial snowbanks'.
North American distribution. Alaska, Yukon, Northwest Territories Islands, continental Northwest Territories, Nunavut Islands, continental Nunavut, northern Quebec, Labrador. Range in the Canadian Arctic Archipelago moderate. Uncommon. Low Arctic. Arctic islands: Baffin, Ellesmere, Axel Heiberg, Parry islands (Melville and Prince Patrick), Banks, Victoria, Southampton, Coats.
Northern hemisphere distribution. Circumpolar. Northern Fennoscandian, Svalbard Franz Joseph Land, Polar Ural Novaya Zemlya, YamalGydan, Taimyr Severnaya Zemlya, AnabarOlenyok, Kharaulakh, YanaKolyma, West Chukotka, West Alaska, North Alaska Yukon, Central Canada, Labrador Hudson Bay, Ellesmere Land Peary Land, West Greenland, East Greenland.
General notes. Nesom and Murray (2004) noted that this taxon has been treated at infraspecific rank within Erigeron uniflorus L., but stated that evidence that might clearly define their biological relationship and appropriate taxonomic rank is not at hand. Erigeron uniflorus sensu stricto occurs in the mountains of northern Europe and Caucasus, mostly south of E. eriocephalus.
Illustrations. • Habitat: Dorset. Plants growing in shelter of overhanging rock. Only a few other plants seen in the area. Nunavut, Baffin Island, Cape Dorset. 4 August, 2005. Aiken. No voucher. • Close-up of plant. Note involucra of purple bracts covered in dense white hairs. Nunavut, Baffin Island, growing in sand on the beach. 23 July, 2005. No voucher. Photograph by Kathy Thornhill. • Close-up of plant. Plants with simple leaves and flowering heads surrounded by pale purple and gray hairy involucral bracts. Young ray florets are white, older ray florets have turned pale lavender. N.W.T., Banks Island, Sachs Harbour. 14 July, 1999. Aiken 99–070. CAN. Scale bar in cm. • Close-up of young flowering head. Flowering head pinkish purple with grey hairy involucral bracts, and young, white ray florets. Adjacent disc florets are beginning to open, but most of the disc florets are greenish and in bud. Aiken 99–070. CAN. • Close-up of flowering head. Flowering head with conspicuous involucra of purple bracts covered in dense white hairs, white ray florets, and yellow disc florets with forked stigmas exposed. Nunavut, Baffin Island, growing in sand on the beach. 23 July, 2005. No voucher. Photograph by Kathy Thornhill. • Close-up of older flowering head. Flowering head with long silky hairs on the pinkish purple involucral bracts, ray florets in which the petals have faded to pale pink and pinkish stigmas can be seen, adjacent disc florets with pale orange, strap-like stigmas and central disc florets that are yellow from almost mature anthers. Aiken 99–070. CAN. • Fly pollination. Flowering head visited by a fly. 23 July, 2005. No voucher. Photograph by Kathy Thornhill. • Contrasting capitula. Left, Erigeron uniflorus subsp. eriocephalus with reflexed phallaries, right, Erigeron humilis with erect or slightly spreading phallaries. Drawing by Mrs. S. Bergh and Mrs. L. Barstad based on a collection from Svalbard, Andrée Land, E. uniflorus subsp. from ytterste fjeld på nordsiden av Purple Valley, sydvendt hylle, ca 450 msm. [outermost mountain on N side of Purple Valley, south facing ledge]. 14 August, 1928. O.A. Høeg. 0 200197. E. humilis from Purpurdalen, ytterste fjell på sørsiden, sørvendt hylle, 450 msm. 14 August, 1928. O.A. Høeg. O 200921. 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..