Taraxacum neoboreale Kirschner & Štěpánek, 2025

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 : 23-24

3. Taraxacum neoboreale Kirschner & Štěpánek , sp. nov.

Type:—[ RUSSIA] Sibiria merid., urbs Irkutsk, lacus Bajkal, pagus Listvjanka , in decl. stepposis supra portum in pago Listvjanka , 26 Oct 1985, J. Kirschner & J. Štěpánek, cultivated from achenes JŠ 1575/72 as JŠ 2715, collected in 1988 ( PRA, no. det. 37772; isotypi: PRA, no. det. 37774) .

Etymology:—Derived from borealis, northern.

Diagnosis:—Species ex affinitate Taraxaci xanthelli, a quo phyllariis involucralibus exterioribus numerosis, late ovatis vel ovatis, conspicue late marginatis, foliis glabrescentibus, acheniis longioribus, pyramide subcylindrica longiore et rostro breviore bene dignoscenda.

Plants medium-sized to small, usually 8–13 cm tall, with a compact, subrobust growth. Plant base without tunic, with subdense arachnoid hairs among petiole bases; petiole broadly winged, initially often sparsely arachnoid, later glabrescent, usually suffused brownish pink. Leaves deep dull green, occasionally with little elongated brown-purple spots, initially sparsely arachnoid, later ± glabrous, oblong or oblong-lanceolate in outline, usually (5–) 6–8 (–11) × (1–) 2–3 cm, usually pinnatilobed (or only pinnatilobulate or remotely dentate), or pinnatipartite, with (4) 5–6 pairs of patent to ± forward-pointing, deltoid, sometimes deltoid-acuminate lateral segments, with distal margin ± subconcave, entire or with a single basal tooth or lobule, proximal margin usually straight, entire, apex acute, seldom acuminate; terminal segment ± suppressed, short and narrower than the rest of the blade, flat-triangular to tricuspidate, margins entire, apex often mucronate, basal lobules patent to forward-pointing, acute; interlobes short and broad, entire, surface green or with submarginal brown-purple spots; mid-vein usually usually suffused brownish purple. Scapes brownish green, sparsely arachnoid, distally more densely so, growing from outside the rosette centre, ± equalling leaves. Capitulum bright yellow, ca. 3.5–4 cm wide. Involucre usually blackish olivaceous or dark olivaceous, not pruinose, 8–10 mm wide and narrowly rounded at base. Outer phyllaries 13–16, appressed, ± not imbricate, broadly ovate to ovate, (6.0–) 6.5–8.0 (–8.5) × (2.9–) 3.3–3.8 (–4.0) mm, broadly bordered, with middle strip ± black-olivaceous, ca. 0.5–1.5 mm wide, bordered light to dark olivaceous (ca. 1 mm), with a whitish membranous or only membranous border 0.5–1.0 mm wide, margin often remotely denticulate, ciliate or glabrous, apex suffused purplish, with thick black horns usually 2–2.5 mm long; inner phyllaries usually of ± invariable width, 13–14 mm long, with dark horns ca. 1.0– 1.5 mm long. Outer ligules flat, faintly striped greyish outside, or almost unstriped, teeth dirty yellow, inner ligule teeth yellow. Pollen abundant, irregular in size. Stigmas pure yellow. Achenes light greyish stramineous-brown, ca. 4.4–4.7 × (1.0–) 1.1 mm, body subdensely covered with short but robust spinules in upper 1/3–1/4, subabruptly to gradually narrowing in subcylindrical cone (0.9–) 1.1–1.3 mm long, ca. 0.4 mm thick at base, ca. 0.3 mm distally; beak 7.5–8.5 mm, pappus white, ca. 6.5 mm long. – Agamospermous. – Fig. 8 , 9 .

Diagnostic notes:—It is similar to T. xanthellum , another species with yellow stigmas, but clearly differs in having outer phyllaries more numerous, of broadly ovate to ovate shape, with a well developed broad paler border, longer achenes with a longer subcylindrical cone, and a shorter beak.

Distribution and habitat:—For the time being, T. neoboreale is known from the broader vicinity of the origin of the Angara River at Lake Baikal. It grows in slopes and shallow depressions in a mosaic of semisteppe and shrubby vegetation.

Specimens examined:— RUSSIA. Irkutsk Region, Lake Baikal, along a road near the village of Listvyanka and around the hill of Pik Cherskogo , 26 Oct 1985, J. Kirschner & J. Štěpánek, cult. as JŠ 2706 ( PRA, no. det. 37776) .

Figures

FIGURE 8. Taraxacum neoboreale. A, general habit (above: PRA, no. det. 37772, one of the holotype plants; below: PRA, no. det. 37774, isotype); B, achenes (PRA, from cultivation JŠ 2715). Scale bars: A = 2 cm; B = 1 mm.

FIGURE 9. Taraxacum neoboreale. The holotype. Photo M. Hladík.