Taraxacum tuvense Krasnoborov

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 : 123

53. Taraxacum tuvense Krasnoborov & A.Krasnikov in Krasnoborov et al. (1984: 537) Type:—[ RUSSIA, Republic of Tuva] Tuvinskaya ASSR, Erzinskiy r-n, nagor’e Sangilen , verchov’ye r. Naryn , verchov’ye ruch’ya

Khap-Sug, osypi u osnovaniya skal izvestnyaka, 2300 m, 8 Jul 1973, I. Krasnoborov & M. Sakovich ( NS, holotype, n. v., but see

Krasnoborov et al. 1984: 538, fig. 1; LE, no. det. 6029, isotype). Etymology:— The Tyva Republic, or Tuva (in Russian), a national region (formerly a state) east of the Altai at the Mongolian border .

Plants relatively slender, usually up to 15 cm, sometimes to 25 cm tall. Petiole long, usually winged, sometimes unwinged, slightly purplish along the vein, subglabrous, tunic absent. Leaves subglabrous, light green, linear-oblong in outline, usually 8–13 (–15) × (1.0–) 1.5–2.0 (–2.5) cm, pinnatilobed to pinnatisect, usually with 2–3 pairs of short, patent deltoid or ± recurved, narrowly triangular, subobtuse to subacute entire lateral segments; terminal segment ± narrowly triangular, entire, subobtuse, basal lobules short, patent. Scapes brownish green, often suffused purplish, ± glabrous, overtopping leaves. Capitulum yellow, to ca. 3 cm wide. Involucre greyish olivaceous-green, ca. 8–9 mm wide and rounded at base. Outer phyllaries ca. 12–13, appressed, subimbricate or not imbricate, ovate to ovate-lanceolate, usually 5.0–6.3 × 2.1–3.0 mm, often suffused pink distally, with a black-green middle part, a paler green zone ca. 0.5–0.9 mm wide, and a very narrow, membranous or whitish-membranous border usually 0.1–0.2 mm, sometimes to 0.5 mm wide, margin ± glabrous, apex usually dark corniculate; inner phyllaries ca. 12–14 mm long, blackish olivaceous-green, flat or ± corniculate. Outer ligules flat, striped grey-purple outside, teeth blackish purple, inner ligule teeth purplish. Stigmas dark discoloured. Pollen present, pollen grains irregular in size. Achenes not seen in the original material; Krasnikov (1997) gives the following features: achenes deep brown, 4–4.5 mm long, cone 0.8–1.0 mm long; beak 6–8 mm long, pappus 7–8 mm long. — Agamospermous. – Fig. 85 .

Diagnostic notes:—The absence of achenes makes any comparison rather difficult. However, there is a species described from (almost) the same locality, T. sangilense Krasnoborov & Khanmichun , having strikingly similar, if not identical, outer phyllaries. The latter has long, almost smooth achenes with a subconical cone. Its differences from T. tuvense include deep purple, long, thin petioles, and undivided spathulate leaves. Further study is needed; T. sangilense was listed among possible members of T. sect. Atrata (Kirschner & Štěpánek 2017: 256).

The sectional position of T. tuvense is inferred from the winged petiole, patent, flat deltoid leaf lateral segments, and usually corniculate outer phyllaries, all pointing to T. sect. Borealia.

Distribution:—Known from the Tuva Republic, probably endemic.

Figures

FIGURE 85. Taraxacum tuvense. A, general habit (LE, no. det. 6029, scale bar = 2 cm); B, a detail of an involucre from the same specimen (scale bar = 5 mm).