Flora of the Canadian Arctic Archipelago
English: Hawk's beard.
Asteraceae (Compositae), Daisy family.
Published in Phytologia 55: 7. 1984.
Type: Canada: Nunavut, Arctic seacoast, Copper-Mine River, leg. Richardson. Holotype: K.
Synonymy. Crepis nana Richardson, in Franklin, Narr. Journey Polar Sea (Bot. App.) 746. 1823.
Crepis nana Richardson var. lyratifolia (Turcz.) Hultén, Ark. Bot., n. s., 7, 1: 144. 1968a.
Vegetative morphology. Plants 1–8 cm high; perennial herbs; without milky juice. Taproot present. Ground level or underground stems absent. Caudex present (slight, stem not visible). Aerial stems a small transition zone between taproot and basal leaves (leaves and flowerings stems prostrate except at the peak of flowering); prostrate (leaves, flowerings stems prostrate except at the peak of flowering). Leaves heterophyllous (when flowering stem leaves are compared with bracts leaves), or not heterophyllous (basal leaves, although they can be rather variable in shape); basal in a rosette; patent; alternate; dying annually and non-persistent. Petioles present, or absent (sometimes merely a narrowing of the blade towards the base of the leaf); (0–)14–25 mm long; glabrous. Leaf blade bases attenuate. Blades 5–20 mm long, 5–10 mm wide, divaricate, rolled in bud (with the margins rolled inwards), linear (initially, as thin stalk-like structures pushing up between the flowers) or oblanceolate or obovate or spatulate (towards the apex of the blade; the leaves are very variable in shape) or lyrate, flat, veins palmate or with inconspicuous veins (usually). Blade adaxial surface glabrous. Blade abaxial surface glabrous. Blades lobed (sometimes with points on the end of the lobes, sometimes somewhat runcinate) or not lobed. Blade margins entire; degree of incision 5–50% (if applicable); apices acute, or obtuse, or rounded.
Reproductive morphology. Flowering stems two or more per plant; shorter than the leaves, or about as high as the leaves; with leaves (usually a small, inconspicuous bract leaf), or without leaves. Inflorescences solitary heads (might be misinterpreted as a single flower). Flowering heads 10–15 mm deep; 2.5–4 mm wide; with only ligulate florets. Involucral bracts present. Number of rows 2–3. Outer involucral bracts mostly green; lying adjacent to the flowers; linear, or lanceolate; 1.5–2.5 mm high; 3–6 mm wide; glabrous. Inner involucral bracts linear, or lanceolate; 9–11 mm high; 0.8–1.5 mm wide; margins wide, scarious for at least one quarter of the bract, or narrow and scarious, less than one quarter of the bract; apex lacerate (sometimes pinkish). Flowers bilaterally symmetrical (zygomorphic). Sepals represented by a pappus. Pappus with a single row of hairs; whitish. Ligulate florets pappus 5.5–6.5 mm long. Petals conventional; fused; 5; yellow (sometimes pinkish from young anthers or after being dried as herbarium specimens). Corolla flat, strap-like; 5-lobed. Ray florets limb 0.9–1.1 mm wide. Ligulate florets limb (8–)9(–10) mm long; 5.2–8.5 mm wide. Stamens 5. Anthers yellow; 2–2.5 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; dry; cypselas; ellipsoid, or ovoid; brown, or straw-coloured; 5–5.5 mm long; 0.4–0.5 mm wide; surface venation ribbed; indehiscent. Seeds 1.
Chromosome information. 2n = 14.
2n (2x) = 14. Babcock (1947, Alaska); Zhukova (1966, 1969, northeastern Asia); Taylor and Brockman (1966, western Canada); Hedberg (1967a, Alaska); Johnson and Packer (1968, northwestern Alaska); Krogulevich (1971, Siberia; 1976, northern Siberia); Krogulevich and Rostovtseva (1984, Siberia); Legge (1971, Alaska, seven counts); Mulligan et al. (1972a); Mulligan and Cody (1973, Yukon); Rostovtseva (1979); Dawe and Murray, in Löve (1979, Alaska); Krogulevich and Rostovtseva (1984); Löve and Löve (1985b, as Askellia nana); Murray and Kelso (1997, western Alaska). Several more southern counts.
Ploidy levels recorded 2x.
Ecology and habitat. Substrates: river terraces, slopes (screes; see image library); dry; gravel, sand; with low organic content; calcareous.
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. Arctic, alpine. Arctic islands: Baffin, Parry islands (Prince Patrick), Banks, Victoria (and Boothia Peninsula).
Northern hemisphere distribution. Amphi-Beringian (broadly). Taimyr Severnaya Zemlya (?), AnabarOlenyok, Kharaulakh, YanaKolyma (?), West Chukotka, Wrangel Island, South Chukotka, East Chukotka, West Alaska, North Alaska Yukon, Central Canada, Labrador Hudson Bay.
General notes. Burt (2000) noted that this plant has a wide range from high passes in Denali National Park, Alaska, to the windswept and spray-lashed beaches of algal limestone islands off the north shore of central North America. It grows on gravel bars in the mouths of arctic rivers that are subject to annual flooding. Its "yellow flowers spread out like a tiny bracelet at the edge of the rosette." (p. 192).
The habit of blooming while the flowering heads still touch the rosette is an adaptation to keep the developing ovaries within the warmest stratum of air close to the ground and the sun-warmed rocks (Savile 1972).
Elven and Murray, in Elven et al. (2005) noted that "the two fairly closely related species previously named as Crepis elegans and C. nana have the base chromosome number of x = 7 (as opposed to 4–6 elsewhere in Crepis), are characteristic morphologically, and have been separated, together with some relatives, as the genus Askellia W.A.Weber, based on Crepis sect. Ixeredopsis Babc." There are good arguments for this solution (see Weber 1984), which has been followed here.
Illustrations. • Habitat. Isolated plants in the foreground with dark green leaves and white heads from the pappus hairs on the fruits. N.W.T., Melville Island, McCormick Inlet. L.J. Gillespie 6971 and L.L. Consaul. CAN. • Close-up of plant. Lyrate leaves, single flowering heads in bud and some that are beginning to open. Note the reddish involucral bracts and relatively few long ligulate petals. Banks Island, Aulavik National Park, banks of the Thomsen River. Aiken 99–038. CAN. • Close-up of flowering plant. Plants with leaves and flowers patent on the tundra. N.W.T., Melville Island, McCormick Inlet. L.J. Gillespie 6971 and L.L. Consaul. CAN. Scale in mm. • Close-up of fly pollination. Note fly on the flowers. Fly pollination occurs in these plants on Melville Island. Flowers are composed of only ligulate petals that have five distinct lobes on the tips of each petal. N.W.T., Melville Island, McCormick Inlet. L.J. Gillespie 6971 and L.L. Consaul. CAN. • Plant beginning to set seed. Rosette plant lying patent on the tundra with leaves and inflorescences that are beginning to set seed. N.W.T., Melville Island, McCormick Inlet. L.J. Gillespie 6971 and L.L. Consaul. CAN. • Close-up of plant beginning to set seed. Centre of the plant with one late inflorescence coming into flower. Flowering head with expanded ligulate florets that have stigmas protruding at the base. Note the flowering heads shedding petals and others developing white fluffy pappus hairs. N.W.T., Melville Island, McCormick Inlet. L.J. Gillespie 6971 and L.L. Consaul. 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..