Taraxacum eurylepium Dahlstedt

Kirschner, Jan, Štěpánek, Jan & Buryy, Vladimir V., 2025, Towards a revision of Taraxacum sect. Borealia (Compositae, Crepidinae) in Siberia and the continental Far East, with special reference to the dandelions of the Altai and Kamchatka, Phytotaxa 679 (1), pp. 1-147 : 74-76

29. Taraxacum eurylepium Dahlstedt in Ostenfeld (1910: 92, fig. 19)

Type:— CANADA. Yukon Territory, Herschel Isl. , 69°35’N, 138°50’W, 17 Jul 1906, A. H. LindstrØm ( O, holotype, n.v., fide Haglund 1948: 304) .

Etymology:—From Greek eurys, broad, and lepis, scale.

Plants small, 2–6 cm tall. Plant base without tunic, subglabrous; petiole winged or narrowly winged, light green or faintly pinkish. Leaves subprostrate to erect-patent, ± mid-green, glabrous, linear-oblanceolate in outline, ca. 2.5–6.0 × ca. 0.7–1.2 cm, ± undivided, most often with 1–3 pairs of ± patent, deltoid or triangular lobules or teeth, terminal leaf part often elongated, usually 1.0– 1.5 cm long, subacute; lateral lobules acute, to ca. 3 mm long, narrower leaf parts between lobules (“interlobes”) ca. 0.7–0.9 cm wide, leaf margin otherwise entire or rarely distal lobule margin with a minute basal tooth; mid-vein green or purplish. Scapes glabrescent, initially sparsely arachnoid, light (brownish) green, sometimes suffused purplish, ± overtopping leaves. Capitulum yellow, 2.5–3.5 cm wide. Involucre dark (blackish) olivaceous-green, 7–9 mm wide and broadly rounded to subtruncate at base. Outer phyllaries 9–11, appressed, subimbricate, broadly ovate to ovate, ca. 5–7 (–8) × 3–4 mm, surface black-green (almost black when dry), distally ± suffused dark purple, almost unbordered or (mainly distally) with a sharply delimited pale border 0.1–0.3 mm wide, margin glabrous, apex with low cornicles; inner phyllaries few, ca. 7–9, broad, blackish-olivaceous, ca. 12–13 mm long. Outer ligules (distally) canaliculate, striped light greyish outside, ligule teeth blackish. Stigmas light discoloured (grey yellow). Pollen absent. Achenes (after Haglund 1948: 304) light greyish olivaceous-brown, ca. 4.8–5.0 × 1.1 mm, body densely covered with short spinules, otherwise tuberculate or rugulose, subgradually narrowing into a subconical cone ca. 0.7 mm long; beak ca. 6 mm, pappus ± white, ca. 6 mm long. – Agamospermous. – Fig. 48 .

Note:—The famous Gjöa expedition (captain R. Amundsen, 1903–1906) had to spend almost two years in an harbour on King William Island, and then more than half a year on Herschel Island. In both regions, plants were collected by Adolf Henrik Lindstrøm, a cook of the expedition, and botanical results were published by C. Ostenfeld (1910). Two dandelions were described on the basis of these collection, T. hyperboreum Dahlstedt in Ostenfeld (1910: 26) and T. eurylepium . While the former name has a rich original material, the type of T. eurylepium is currently missing. We therefore had to interpret the name T. eurylepium according to the protologue (including a photograph of the type plant) and to the new material collected on Herschel Island.

Diagnostic notes:— Taraxacum eurylepium obviously occupies a position intermediate between T. sect. Borealia and T. sect. Arctica, perhaps closer to the former. It is distinct in having a robust capitulum, a broadly rounded broad involucre base, and broadly ovate outer phyllaries; it is characterized by the absence of pollen and densely spinulose light greyish brown achenes.

Distribution and habitat:—Originally known from Herschel Island, the northernmost Yukon Territory (documented by a number of gatherings), then reported from the W. Alaska ( Haglund 1946: 343), and from the Russian territory (Herald Isl.). It is reported from tundra communities.

Specimens examined:— CANADA. Yukon Territory, Herschel Isl., 69°34.5’N, 138°56’W, 9 Jul 1976, P. F. Cooper 121 ( NY 2919099 , photo!). – Canada, Yukon Territory, Herschel Isl. , between 69°36’N 139°03’W and 69°36’N 138°57’W, 11 Jul 1976, P. F. Cooper 168 ( NY 2919100 , photo!) . – RUSSIA. Herald Isl. , 1881, C. L. Hooper ( US 424060, n. v., fide Haglund 1946: 344).

Figures

FIGURE 48. Taraxacum eurylepium. General habit (US 2919099).