Taraxacum indulgens Štěpánek & Kirschner, 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

8. Taraxacum indulgens Štěpánek & Kirschner , sp. nov.

Type:— RUSSIA. Republic of Tuva, Erzin, 3 km W of village Moren , flat valley of river Erzin , steppe with extrazonal forest of Larix , Betula , Picea obovata , Populus laurifolia on gravel bank, 940 m, 50°18’05” N, 95°19’25” E, 30 Jun 2013, J. Vondrák & I. Frolov, cultivated from achenes “ Tuva 3” as JŠ 9928, collected in 2015 ( PRA, no. det. 36784 holotype; isotype: PRA, no. det. 36786, with numerous duplicates).

Etymology:—Indulgent, lenient, benevolent.

Exsiccates:— Taraxaca Exs., no. 1356.

Diagnosis:—Plantae Taraxaci ledebourii affines sed differunt achenii colore, pyramide longiori, phyllariis exterioribus brevioribus, ceterum etiam phyllariis paucis laxe adpressis late ovatis pallide viridibus et acheniis brevibus notabiles.

Plants small or medium-sized, 9–12 cm tall, later up to 18 cm tall. Petiole narrow, unwinged or very narrowly winged, usually 2–4 cm long, inconspicuously light greyish brown-purple, ± densely arachnoid; plant base with tunic, densely dirty white arachnoid among petiole bases. Leaves numerous, subprostrate to erect-patent or ascending, narrowly oblanceolate to linear-oblanceolate in outline, 5–10 × 1.2–2.5 cm, not spotted, ± sparsely arachnoid along and on mid-vein, regularly pinnatisect; lateral segments in 4–5 (6) pairs, ± patent, linear or narrowly lingulate, usually 5–11 × 1–2 mm, acute to acuminate, distal margin subconvex to subsigmoid, entire or with a single minute tooth, proximal margin subsigmoid to subconcave, entire; terminal segment relatively small, usually 6–14 × 8–14 mm, ± triangular in outline, sometimes ± helmet-shaped, usually trilobed with its terminal part lingulate to narrowly lanceolate, entire, basal lobules patent, narrowly lingulate to narrowly oblong, ca. 3–6 mm long, acute, entire; interlobes narrow, usually 5–8 × 1.5–3 mm, unbordered, not blotched, entire or with 1–2 narrow acute teeth or lobules; mid-vein adaxially ± densely arachnoid, purplish to brownish, rarely light green. Scapes ± densely arachnoid, suffused brown-purple at base and distally, otherwise lighter brownish-purplish, ± equalling leaves. Capitulum yellow, ca. 3 cm wide, ± flat. Involucre rounded at base. Outer phyllaries 9–11, loosely appressed to erect, subimbricate or not imbricate, broadly ovate to ovate (upper up to ovate-lanceolate), reaching 2/5–1/2 of the inner, usually 5–6 × (3–) 4–4.5 mm, surface light green (pale green in early capitula), often with a dark, blackish, thin middle line, with a gradual transition in a membranous, translucent border 0.3–0.5 mm wide, margin irregularly minutely ciliate, apex flat; inner phyllaries ca. 11 mm long, of ± unequal width. Outer ligules flat, striped purplish grey-olivaceous outside, teeth red-brown, inner ligule teeth dark yellow to reddish. Stigmas ± light discoloured, light greyish yellow-green, with dark pubescence outside. Pollen present, pollen grains irregular in size. Achenes red-brown to castaneous, with a silvery hue when fully ripe, short and relatively thick, usually (3.4–) 3.6–3.8 × 0.9–1.0 mm, body subdensely to densely spinulose in upper 1/3, with spinules erect-patent, thin, up to 0.3 mm long, body ± abruptly narrowing into a thin cylindrical cone (0.8–) 0.9–1.0 mm long, often with 1 (–2) spinules at base; beak 8–9.5 mm long; pappus ± dirty white, ca. 6 mm long. – Agamosperm. – Fig. 9 .

Diagnostic notes:— Taraxacum indulgens is distinct in having few, broadly ovate to ovate, light green outer phyllaries usually 4–4.5 mm wide, with a very gradual transition from green middle part towards membranous borders, and achenes short, relatively thick, red-brown to castaneous, with a thin cylindrical cone. Taraxacum ledebourii is similar in its leaf shape but different in the achene colour, a much shorter cone, paler stigmas and longer outer phyllaries.

Distribution and habitat:— Taraxacum indulgens is known from a single macrolocality in the Tuva Republic; it grows in a steppe habitat on gravel at locally relatively low elevation below 1000 m.

Figures

FIGURE 9. Taraxacum indulgens. A, details of flower heads and leaves (live plants from the cultivation JŠ 9928). Scale bar = 1 cm. B, a detail of involucre (the same cultivation, another plant).