Taraxacum roseolum Kirschner & Štěpánek, 2017

Kirschner, Jan & Štěpánek, Jan, 2017, A revision of Taraxacum sect. Atrata, a dandelion group centred in the Middle Asia, and the problem of Taraxacum brevirostre, Phytotaxa 305 (4), pp. 225-261 : 250-251

15. Taraxacum roseolum Kirschner & Štěpánek , sp. nova.

Type: — KYRGYZSTAN. Ysyk Kol [Issik-kul] Province, Ak-Su Region, Terskey Ala-Too, valley of Saryzhaz River, southern slopes at 3600 m, in the vicinity of 42°25‘44“N, 79°35‘10“E, 2014, I. Ulbrichová s.n. Cultivated from achenes under no. JK6962B ( PRA, no. det. 28150, holotype).

Diagnosis: — Plantae graciles glaberrimae, foliis pinnatisectis, lobis lateralibus 2–3 patentibus, phyllariis involucralibus exterioribus atro-viridibus, lanceolatis vel late lanceolatis erectis vel erecto-patentibus, saepissime immarginatis, capitulis saturate, raro pallide roseis, antheris polline carentibus, stigmatibus griseo-viridibus, acheniis griseo-stramineis, ± laevibus, rostro incrassato.

Description: —Plants small, usually 5–9 (–11) cm tall. Petiole dark green, often suffused dark purplish, narrowly winged in outer leaves, unwinged and narrow in middle and inner ones, glabrous, plant base without remnants of old petioles. Leaves deep green to mid-green, mid-vein green to bordered brownish purple, oblanceolate to spathulate in outline, usually 3–7 (–8) × 1.3–2.0 cm, glabrous, usually pinnatisect, with 2–3 pairs of linear-triangular, patent to subrecurved entire lateral segments, often with distal margin concave (with a broader base abruptly narrowing into broadly linear distal part) or straight; terminal segment subobtuse, sometimes helmet-shaped, with a pair of narrowly triangular to lingulate basal lobules. Scapes purplish brown-green at base, otherwise green, glabrous, overtopping leaves. Capitulum 3–5 cm wide. Involucre blackish green to blackish, not pruinose, ca 8–10 mm wide, ± rounded at base. Outer phyllaries 11–15, ± not imbricate, lanceolate to broadly so, usually 6–8.5 × 2–3.5 mm, erect to erect-patent, unbordered or an indistinct pale border to 0.1 mm wide, rarely (when phyllaries generally paler) broader paler borders developed at phyllary base or or along the whole margin and then to 0.3 mm wide, phyllary surface black-green with blackish-purplish tip, margins glabrous, apex ± flat, callose or minutely corniculate; inner phyllaries 12–15 mm long, dark green, ± flat. Capitulum colour deep pink with a slight purple hue in outer ligules, slightly paler in the inner ones, some, often later capitula paler, light pink to whitish lilac, outer ligules flat, inconspicuously striped purplish or greyish pink outside, inner ligule teeth whitish pink, pink purplish in more outer ligules. Stigmas greyish green, with dark pubescence outside. Pollen absent. Achenes light greyish straw-brown, 5.2–5.6 × 1.0– 1.1 mm, body generally smooth, often with almost invisible minute squamules or tubercles above, cone not developed, part above the tubercles thick, ca 0.5 mm long, gradually narrowing into beak; beak easily breaking off, 3–4 mm long, thickened (over 0.2 mm thick), pappus ± white, 5.5–6 mm long.—Agamospermous.— Fig. 18B , 19.

Comparison with other taxa: — Taraxacum roseolum leaves resemble those of the T. arcticum agg. of T. sect. Arctica. However, all the achene characters point to T. sect. Atrata. Within the latter section, T. roseolum is distinct in having outer phyllaries erect to erect-patent. In combination with the lacking pollen, flower colour and the total glabrescence of the plants, T. roseolum is a distinctive taxon. Known from the type locality ( Fig. 23 ).

Specimens examined: — KYRGYZSTAN. Ysyk Kol [Issik-kul] Province, Ak-Su Region, Terskey Ala-Too, valley of Saryzhaz River, southern slopes at 3600 m, in the vicinity of 42°25‘44“N, 79°35‘10“E, 2014, I. Ulbrichová s.n. Cultivated from achenes under no. JK6962B (isotypi: PRA, no. det. 28151, 28152, 28153, 28154, 28155, 28156, 28157, 28158, 28159, 28160).

Figures

FIGURE 18. Achenes of (A) T. roseiflos (PRA, no. det. 28146) and (B) T. roseolum (PRA, no. det. 28150). Scale bar = 1 mm.

FIGURE 23. Distribution ranges of T. alpigenum (square), T. roseolum (triangle), T. sinotianschanicum (circle), T. smirnovii (hexagon), and T. subglaciale (octagon).