Flora of the Canadian Arctic Archipelago
Asteraceae (Compositae), Daisy family.
Published in Fl. Saxon. 146. 1842.
Synonymy. Cineraria taxon Tephroseris Rchb., Fl. Germ. Excurs. 241. 1831.
Vegetative morphology. Plants (4–)10–40(–60) cm high; annual herbs, or biennial herbs, or perennial herbs. Only fibrous roots present. Ground level or underground stems horizontal, or absent. Caudex absent. Aerial stems erect. Aerial stem trichomes appressed, or spreading. Leaves heterophyllous, or not heterophyllous; mainly basal and distributed along the stems; erect (or spreading); alternate; dying annually and non-persistent. Petioles present, or absent (long attenuated leaf blade bases may appear petiole-like); 0–30 mm long (if applicable); glabrous (if applicable). Leaf blade bases truncate, or attenuate, or rounded. Blades (1.5–)8–20(–30) mm long, (1–)3–20(–27) mm wide, spreading (basal leaves) or appressed to the stem (stem leaves), linear or circular or lanceolate or ovate or obovate, flat, with three main veins or appearing single-veined. Blade adaxial surface glabrous or hairy, hairs puberulent or pubescent or pilose or woolly, hairs simple, hairs moderately dense, hairs white, or translucent or tawny. Blade abaxial surface glabrous or glabrescent or hairy, hairs woolly (if applicable), hairs sparse or moderately dense or very dense, hairs white or rust-coloured, hairs straight or wavy, hairs appressed or spreading. Blade margins entire or dentate or runcinate, glabrous or with non-glandular hairs, with 0–6 teeth on each side of the blade (if applicable), with teeth toward the apex (rarely on the lower half of the blade, if applicable); degree of incision 1–60% (if applicable); apices acuminate, or acute, or obtuse, or rounded.
Reproductive morphology. Flowering stems with leaves; woolly (if applicable). Flowering stem hairs simple; white or translucent, or brown (from colour in the end walls of multicellular, floccose hairs). Inflorescences solitary heads, or of several flowering heads. Flowering heads 8–20 mm deep; (12–)20–35(–40) mm wide; with only disc florets, or with disc and ray florets (usually). Pedicels absent, or subtending flowering heads; with non-glandular hairs (if applicable). Involucral bracts present. Number of rows 1–2. Outer involucral bracts mostly green (tips and edges can be dark and red pigmented), or mostly wine red or purple pigmented; lying adjacent to the flowers; oblong, or lanceolate, or obovate; 2.5–6 mm high; 0.5–2(–2.3) mm wide; sparsely hairy, or densely hairy; without glandular hairs. Inner involucral bracts linear, or lanceolate; 2.5–5 mm high; 0.5–0.7 mm wide; margins wide, scarious for at least one quarter of the bract. Flowers radially symmetrical (actinomorphic), or bilaterally symmetrical (zygomorphic); unisexual, or bisexual. Sepals represented by a pappus. Pappus with a single row of hairs, or with a double row of hairs; whitish. Ray florets pappus 1.5–12(–15) mm long. Disc florets pappus 1.5–8(–12) mm long. Petals conventional; fused; 5; yellow; 3–8 mm long. Corolla tubular, or funnel-form, or flat, strap-like; 2-lobed to 3-lobed (ray florets), or 5-lobed (disc florets). Ray florets 7–20; limb 3.5–20 mm long; limb 0.5–3 mm wide. Stamens 5. Anthers yellow; 1.4–2.5 mm long. Ovary inferior; carpels 2; syncarpous. Styles 1; 5–8 mm long. Stigmas per ovary 2. Placentation basal. Ovules per ovary 1. Fruit sessile; with calyx persisting; dry; cypselas; elongate-cylindrical, or oblong; brown; 1.8–3.5 mm long; 0.3–0.8 mm wide; surface venation ribbed (longitudinally); indehiscent. Seeds 1.
Chromosome information. 2n = 24, or 25, or 48, or 80, or 96.
Ploidy levels recorded 3x/4x/6x/10x/12x.
General notes. Barkley (1999), discussing the segregates of Senecio that are to be recognised in the Flora of North America treatment, stated that the notions leading to these narrower generic concepts are noted in Bremer (1994) and in several papers that were presented at the Compositae Conference at Kew in the summer of 1994 (Hind and Beentje 1996). He provided a synoptic key, stating that nobody doubts the biological significance of the first couplet but the characters used are impractical for routine plant identification. The first couplet separates the Tussilagininae, which includes Tephroseris, and the Senecioninae, which includes Packera and Senecio.
1. Stigmatic areas confluent on adaxial faces of style branches; anther collars cylindrical and cells not inflated; mostly n = 30, or polyploidy/dysploid derivatives ... Tussilagininae
1. Stigmatic areas marginal and distinct on distal, adaxial faces of style branches; anther collars swollen with basal cells inflated; n = (10) 20, or 22–23, or polyploidy derivatives (rarely genus Pericallis) ... Senecioninae.
Barkley (1999) recognised genus Tephroseris within the Tussilagininae as a group of some 40–50 boreal and alpine herbs, centred in Eurasia. The group was revised by Cufodontis (1933), and since then has been treated chiefly in floristic studies with differing species concepts (e.g., Barkley 1978, Cody 1996, Hultén 1968b, Scoggan 1979, Welsh 1974). Elven (personal communication, 2005) recognised 5(-8) taxa in arctic northwestern North America: T. palustris subsp. congesta, T. lindstroemii (and the closely related T. integrifolia, but as uncertainly American), T. frigida (and the closely related T. atropurpurea and T. subfrigida, but both not fully confirmed as American), T. kjellmanii, and T. yukonensis. Barkley and Murray (2006) recognise six taxa: T. palustris, T. lindstroemii, T. frigida, T. kjellmanii, T. tundricola (included in T. lindroemii in Russian treatments), and T. yukonensis.
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..