Taraxacum rubiginans Dahlstedt (1930: 227)

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 : 95-96

38. Taraxacum rubiginans Dahlstedt (1930: 227)

Type:—[ RUSSIA, Kamchatka] Kamtschatka centralis, Anauna river, in the alpine region, 19 Aug 1926, R. Malaise 314 ( S 11-21380 !, holotype; isotype: LE, no. det. 6037) .

Etymology:—Getting rusty or rust-coloured.

Note:—A species intermediate between T. sect. Arctica and T. sect. Borealia. The broadly winged petioles of outer leaves point to the latter section; they are visible on the earlier plants present in S 11-21380. The main problem of the name interpretation is the scanty, mostly rather late original material.

Plants small, to ca. 10 cm tall. Petiole green, broadly winged in outer middle leaves, narrow, unwinged in later, inner leaves. Leaves greyish mid-green, ± glabrous, oblanceolate in outline, usually ca. 4–6 (–7) × 1.2–1.9 cm, early middle leaves with 1–3 short, ± patent, broadly deltoid to deltoid-triangular, ±entire lateral segments and terminal segment broadly flat-triangular, subacute, inner leaves pinnatisect, with 2–3 pairs of subrecurved, narrowly triangular or bird-wing-shaped subentire lateral segments and a triangular, acute terminal segment; interlobes usually with a few, remote, short teeth; mid-vein usually purplish. Scapes brownish green, suffused purplish, subglabrous, overtopping inflorescence. Capitulum yellow, ca. 3.0– 3.5 cm wide. Involucre black-green, ca. 8 mm wide and broadly rounded at base. Outer phyllaries 13–14, appressed, ± imbricate, broadly ovate to ovate-lanceolate, ± acuminate, ca. 4–5 (–7) × (2.3–) 2.5–3.0 mm, surface ± evenly black-green, with black middle line and black-purple apex, border invisible or very narrow, inconspicuous, membranous 0.1–0.2 (–0.3) mm wide, margin ± glabrous, apex flat to callose; inner phyllaries 12–13 mm long, flat or callose. Outer ligules flat, usually striped greenish grey outside, teeth blackish. Stigma dark discoloured. Pollen (probably) absent. Achenes reddish brown, (4.5–) 4.8–5.3 × 1.0– 1.1 mm, body sparsely to subdensely spinulose in upper 1/4–1/3, ± gradually narrowing into a conical cone 0.8–1.0 mm long, ca. 0.5–0.6 mm thick at base, ca. 0.4 mm distally; beak thin, ca. 9–10 mm long, pappus white, ca. 6.5–7.0 mm long. – Fig. 64 , 65 .

Diagnostic notes:—From species of T. sect. Arctica Dahlstedt (1921: 37), it differs in having broadly winged petioles in early middle leaves and a long beak. The reddish brown, relatively long achenes with a conical, relatively thick cone, imbricate outer phyllaries with a very narrow, indistinct or almost invisible border represent the diagnostic characters. Achene shape, leaf shape and imbricate outer phyllaries distinguish it from T. rufum . In the features of outer phyllaries and leaves, T. rubiginans approaches T. anadyrense but the achenes are diagnostic.

Distribution:—Known from several localities in Bystrinskiy District in Central Kamchatka. It grows in tundra habitats and mountain grasslands.

Specimens examined:— RUSSIA. Kamchatka, Bystrinskiy District, NW part of the Nature Park , 56°29.506’N, 158°20.642’E, 493 m, 3 Aug 2014, V. V. Buryy (herb. V. V. Buryy, no. det. 36925) . – Kamchatka, Bystrinskiy District, Ichinskaya Sopka, 3 km W of Lake Ketachan , upper stream of R. Rassoshina , 55°36.127’N, 157°30.046’E, 1400 m, 8 Aug 2017, V. V. Buryy T093 (herb. V. V. Buryy, no. det. 36906) . – Kamchatka, Bystrinskiy District, vicinity of village of Esso, Kozyrevskiy Khrebet , 55°53.852’N, 158°48.458’E, 1319 m, 15 Aug 2015, V. V. Buryy T060 (herb. V. V. Buryy, no. det. 36904) .

Figures

FIGURE 64. Taraxacum rubiginans. A, a detail of involucre (S 11-21380); B, a leaf with broadly winged petiole (S 11-21380, most leaves on the type specimens have petioles ± unwinged). Scale bars: A = 5 mm, B = 1 cm.

FIGURE 65. Taraxacum rubiginans. General habit and a detail of achenes (LE, no. det. 6037). Scale bar = 1 mm.