Taraxacum ledebourii 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

18. Taraxacum ledebourii 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 2551 ( PRA, no. det. 35971, holotype; isotypi: PRA, no. det. 36716) .

Etymology:—Named after the most renowned botanist in Russia in the 19 th century, Carl Friedrich von Ledebour (1786–1851).

Exsiccates:— Taraxaca Exs., no. 1377–1379.

Diagnosis:—Species distinctissima foliis subglabris, interlobiis margine colorato, phyllariis involucralibus exterioribus subimbricatis ovatis usque lanceolatis, marginibus membranaceis viridescentibus 0.5–1.0 mm latis, stigmatibus luteis vel sordide luteis, acheniis pallide griseo-stramineis, corpore superne subsparse distincte spinuloso, in pyramidem subcylindricam 0.5–0.7 mm longam sensim transeunte.

Plants small, usually to 12 cm tall. Petiole narrow, unwinged, subglabrous to sparsely arachnoid, green or faintly suffused pinkish; plant base with yellowish hairs, tunic developed. Leaves mid green, usually subglabrous, often entirely narrowly bordered brown-purple, or dark border confined to interlobes; oblong to linear-oblanceolate in outline, usually 7–11 × (1.0–) 1.5–2.5 cm, deeply pinnatisect; lateral segments usually 4–5 pairs, sometimes deltoid-triangular, usually very narrowly triangular or linear-triangular, patent to recurved, rarely to subhamate-recurved, often narrowed from a broader base into a narrow distal part, distal margin straight, sigmoid to subconcave, sometimes entire, usually with a few little teeth closer to the base, often with a parallel lobule near the distal base, proximal margin straight to sigmoid, usually entire; terminal lobe triangular to tripartite, distal margin subconcave to concave, entire or with 1–2 shallow incisions, basal lobules patent to subrecurved, proximal margin ± straight, entire, patent to subrecurved; mid-vein pale green or suffused pinkish. Scapes brownish green, arachnoid, subequalling leaves. Capitulum yellow, usually 2.5–3.5 cm wide. Involucre light green, 8–11 mm wide and narrowly rounded at base. Outer phyllaries 11–16 (17), appressed, subimbricate, ovate to lanceolate, (6.8–) 7.5–8.5 (–9.5) × (2.7–) 3.2–3.9 (–4.8) mm, with a mid-green to dark green middle part, with a gradual transition into a whitish green or marginally membranous-green paler zone usually 0.5–1.0 mm wide, margin sparsely and minutely ciliate, apex darker, ± flat; inner phyllaries usually 13–14 mm long, flat. Outer ligules striped greyish to faintly greyish, inner ligule teeth dirty yellow or pale purplish. Stigmas yellow or ± dirty yellow. Pollen present, pollen grains irregular in size. Achenes light greyish stramineous-brown, (3.4–) 3.6–3.8 (–4.1) × (0.7–) 0.8 mm, body subsparsely spinulose in upper 1/4, spinules distinct erect-patent, the uppermost ones longest, often almost subpatent, body with a gradual transition into a subcylindrical cone usually 0.5–0.7 × 0.25 mm (cone base often with a few short spinules); beak 9 (–10) mm long, pappus 5–5.5 mm, yellowish white. – Agamosperm. – Fig. 20 .

Diagnostic notes:—The diagnostic and rather unusual combination of characters includes numerous, subimbricate, broadly and distinctly bordered outer phyllaries, yellow or almost yellow stigmas, greyish slender achenes with erectpatent to subpatent spinules and a gradual transition into a relatively short subcylindrical cone.

Distribution and habitat:—A relatively widely distributed south-central Siberian species known from the vicinity of the Bratsk Reservoir, Irkutsk Region, from the Republic of Khakassia and from a series of localities in the Altai (districts of Ongudai, Ust-Ulagan and Kosh-Agach). Dry steppe or semiruderal sites in the Altai, and the gravelly and sandy places near Bratsk, between 400 and 1900 m, are occupied by several species of T. sect. Dissecta , including T. ledebourii .

Specimens examined:—[ RUSSIA, Respublika Altay] SW. Siberia, Altai Mts., Ongudai District, in the valley of Chuya River , in the vicinity of Chepkan village , 2 Jul 1988, J. Kirschner, cultivated as JŠ 3354 ( PRA, no. det. 36726). – Altai Mts., Ongudai District , saline meadows in the vicinity of Aktash village , ca. 1800 m, 4–5 Jul 1988, J. Kirschner, cultivated as JK 15 ( PRA, no. det. 36713). – Ibidem , cultivated as JK 16 ( PRA, no. det. 36728). – Ibidem , dry sites along the road, cultivated as JK 42 ( PRA, no. det. 36715). – SW. Siberia , Altai Mts., Aigulak Khrebet ( Ridge ), district of Ust-Ulagan , at the Ulaganskiy Pereval ( Pass ) near the lakes of Myortvye Ozera , 2 Jul 1988, J. Kirschner, cultivated as JŠ 3365 ( PRA, no. det. 36723). – SW. Siberia , Altai, Kosh-Agach District , valley of the river Chuya , village of Chagan-Uzun , sandy and gravelly sites near the mouth of river Kuyakh-Tonar , ca. 1900 m, 5 Jul 1988, J. Kirschner, cultivated as JK 29 ( PRA, no. det. 36717). – Ibidem , cultivated as JK 17 ( PRA, no. det. 36721). – SW. Siberia , Altai Mts., Ongudai District , steppe sites along the road, about 54 km E. of the confluence of Katun’ and Chuya rivers, 2 Jul 1988, J. Kirschner, cultivated as JK 82 ( PRA, no. det. 36719). – 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 2551 ( PRA, no. det. 36716). – Ibidem , cultivated as JŠ 2554 ( PRA, no. det. 36724); JŠ 2582 ( PRA, no. det. 36722); JŠ 2553 ( PRA, no. det. 36720); JŠ 2552 ( PRA, no. det. 36718); JŠ 2555 ( PRA, no. det. 36712). – Republic of Khakasia, 20 km N of town Shira , quartzite, limestone and schist outcrops in short-grass steppe, 410 m, 54°39’48” N, 89°50’35” E, 18 Jun 2013, J. Vondrák & I. Frolov, cultivated as JŠ 9926 ( PRA, no. det. 36963) .

Figures

FIGURE 20. Taraxacum ledebourii. A, General habit; B, Achenes (both from PRA, no. det. 35971, holotype).