Taraxacum subcollinum Kirschner & Štěpánek, 2023

Kirschner, Jan & Štěpánek, Jan, 2023, A taxonomic revision of Taraxacum sect. Dissecta, a continental steppe group common in Siberia and adjacent regions of Central Asia, Phytotaxa 590 (1), pp. 1921-1935 : 1921-1935

13. Taraxacum subcollinum Kirschner & Štěpánek , sp. nov.

Type:—[ RUSSIA, Irkutskaya oblast] Sibiria merid., urbs Bratsk, ad ripam sinistram lacus structilis “Bratskoe More”, ca. 10 km situ a vallo, ad marg. partis centralis urbis Bratsk, haud procul a deversorio “Bratsk”, 27–28 Oct 1985, J. Kirschner & J. Štěpánek, cultivated as JŠ 2700 ( PRA, no. det. 35967, holotype; isotype: PRA, no. det. 36683) .

Etymology:—Similar to T. collinum .

Exsiccates:— Taraxaca Exs., no. 1372–1375.

Diagnosis:—Species notabilis phyllariis involucralibus exterioribus numero 11–13, adpressis, aequabiliter saturate vel obscure olivaceoviridibus, margine inconspicue anguste membranaceis, stigmatibus luteis vel sordide luteis, acheniis pallide griseo-brunneis, 4.2– 4.9 mm longis corpore angusto, superne spinulis et squamulis tricuspidatis conspicuis tecto, in pyramidem anguste cylindricam 1.1–1.3 mm longam sensim transeunte.

Plants small, rarely to medium-sized, usually to 10–12 cm tall. Petiole green or purplish, sparsely arachnoid, narrowly winged to winged in at least some leaves, unwinged in the other ones; plant base with yellowish hairs, tunic ± developed. Leaves deep green to mid-green, not spotted, sparsely arachnoid to subglabrous, narrowly oblong-oblanceolate in outline, usually 7–11 × 1.8–3.0 cm, most leaves pinnatisect, but usually some pinnatilobed or undivided, sinuate dentate, with 3–5 pairs of patent, narrowly triangular to linear-triangular lateral segments, distal margin most often concave and entire, sometimes with a basal shallow incision or a tooth, proximal margin straight to subconvex, entire or with one or a few minute teeth; terminal segment ± triangular to tripartite, with basal lobules ± patent, margins usually entire; interlobes variable, narrow in pinnatisect leaves, usually 5–7 × 2–3 mm, to 6–8 mm wide in pinnatilobed leaves, usually with 1–4 little teeth or short lobules, sometimes entire; mid-vein often suffused bronze. Scapes brownish green, arachnoid, equalling, sometimes overtopping leaves. Capitulum yellow, usually 3–3.5 cm wide. Involucre deep olivaceous-green or dark green, usually 8–9 mm wide and broadly rounded at base. Outer phyllaries usually 11–13, appressed, not imbricate, ovate to ovate-lanceolate, usually 5–6.5 × 2.5–3.6 mm, evenly deep olivaceous-green, often with lighter green basal part and darker apical one, sometimes with a visible thin blackish middle line, border indistinct, membranous or greenish membranous, 0.1–0.4 mm wide, margin ciliate to subglabrous, apex flat to minutely dark corniculate; inner phyllaries 13–15 mm, elongating to reach 20 mm after anthesis, ± flat. Outer ligules flat, striped greyish or pinkish grey, inner ligule teeth grey to grey-purple. Stigmas yellow to dirty yellow. Pollen present, pollen grains irregular in size. Achenes light grey, long and slender, (4.2–) 4.5–4.7 (–4.9) × 0.7–0.9 mm, body covered with long acuminate suberect spinules and tricuspidate squamules in upper 1/4, gradually narrowing into a thin cylindrical cone 1.1–1.3 × 0.2 mm; beak (8–) 9–10 mm, pappus yellowish white, 5–6 mm long. – Agamosperm. – Fig. 15 .

Diagnostic notes:—The long, slender achenes with long suberect spinules and a long, thin, cylindrical cone are unique in T. sect. Dissecta , and could be only compared with those of T. pubescens . Outer phyllaries are ± borderless, and there is a frequent heterophylly.

Distribution and habitat:— Taraxacum subcollinum is known from a series of gatherings sampled along the western shore of the Bratsk reservoir, on gravelly and sandy sites, at about 400 m a.s.l.

Specimens examined:—[ RUSSIA, Irkutskaya oblast] S. Siberia, town of Bratsk , west shore of the “Bratskoe More” reservoir, about 10 km from the dam, margin of town centre, not far from the “Bratsk” hotel, 27–28 Oct 1985, J. Kirschner & J. Štěpánek, cultivated as JŠ 2700 ( PRA, no. det. 36683, with duplicates). – S. Siberia, town of Bratsk, west shore of the “Bratskoe More” reservoir, about 10 km from the dam, not far from the “Bratsk” hotel, 27–28 Oct 1985, J. Kirschner & J. Štěpánek, cultivated as JŠ 2579 ( PRA, no. det. 36685). – Ibidem, cultivated as JŠ 2699 ( PRA, no. det. 36690). – Ibidem, cultivated as JŠ 2701 ( PRA, no. det. 36692). – Ibidem, cultivated as JŠ 2581 ( PRA, no. det. 36689). – Ibidem, cultivated as JŠ 2580 ( PRA, no. det. 36687) .

Figures

FIGURE 15. Taraxacum subcollinum. A, General habit; B, Achenes (both from PRA, no. det. 35967, holotype).