Taraxacum trepidans 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

10. Taraxacum trepidans Kirschner & Štěpánek , sp. nov.

Type:—[ RUSSIA, Respublika Altay] Sibiria austro-occid., montes Altaj, distr. Ongudaj, in siccis et alluvionibus ad confluentem fl. Katuň et Čuja , 1 Jul 1988, J. Kirschner, cultivated from achenes of JŠ 3457 as T 201 ( PRA, no. det. 35854, holotype; isotype: PRA, no. det. 36675) .

Etymology:—Panicking, trembling.

Diagnosis:—Species distinctissima foliis subglabris, segmentis lateralibus hamato-triangularibus, phyllariis exterioribus late ovatis usque ovato-lanceolatis, variegatis, limbo distincto albo-membranaceo 0.4–0.6 mm lato in zonam pallidam 0.5–1.0 mm latam gradatim transeunte, stria mediana obscure griseo-olivacea, acheniis pallide brunneis leviter rubescentibus, corpore in pyramidem anguste cylindricam 0.5–0.8 mm longam subabrupte transeunte.

Plants small to medium-sized, usually 12–16 cm tall. Petiole usually narrowly winged, deep purple, subglabrous; plant base with ± sparse brownish hairs, tunic developed. Leaves ± mid-green, almost glabrous, oblanceolate in outline, usually 6–9.5 × 1.5–2.5 cm, pinnatisect, with 3–4 (5) pairs of hamate-triangular to hamate-deltoid, recurved to subrecurved lateral segments, distal margin very convex or almost straight, entire or sparsely denticulate, sometimes with a big tooth, proximal margin straight to subconvex, often with a raised margin near segment’s base, usually entire, sometimes with 1–2 minute teeth; interlobes ± broad, usually 4–7 mm wide, usually short, with a single tooth, or a few little teeth, and/or with an acute lobule, often with raised margins; terminal segment triangular to helmet-shaped, often mucronate, usually entire; mid-vein suffused dark purplish. Scape brownish green or pale so, sparsely arachnoid, ± overtopping leaves. Capitulum yellow, 3–3.5 cm wide. Involucre ca. 9 mm wide and rounded at base. Outer phyllaries (10) 12–14 (16), appressed, subimbricate, broadly ovate, ovate or ovate lanceolate, usually 5.8–7.2 × 2.7–3.7 (–5.2) mm, of contrasting colours, with a whitish-membranous border (0.2–) 0.4–0.6 mm wide, distally suffused pinkish, with a gradual transition into a paler, yellow-green zone 0.5–1.0 mm wide and a dark grey-green middle strip, margin ciliate, apex darker, callose, sometimes corniculate; inner phyllaries 11–13 mm long, broad, flat. Ligules flat, striped black or black-purple outside, inner ligule teeth blackish. Stigmas dark discoloured, yellow-green with ± black pubescence outside, sometimes ± light discoloured. Pollen present, pollen grains irregular in size. Achenes light to medium brownish beige, with a variable density of pinkish tinge distally, 3.5–4.0 × 0.8–0.9 mm, body subdensely spinulose in upper 1/3, spinules medium-sized, erect-patent, distal spinules thicker, body subabruptly narrowing into a ± cylindrical cone 0.5–0.8 × 0.2 mm; beak 8–8.5 mm, pappus ± white, 5.5–6 mm long. – Agamosperm. – Fig. 11 .

Diagnostic notes:—The combination of ovate, broadly bordered outer phyllaries of contrasting colours, leaves with hamate-triangular lateral segments and the peculiar brownish beige achene colour makes T. trepidans one of the most distinctive members of T. sect. Dissecta .

Distribution and habitat:— Taraxacum trepidans is known from a series of macrolocalities in Altai Republic, Russia. It grows in a mosaic of gravelly patches, substeppe grasslands with low vegetation coverage and subruderal places.

Specimens examined:—[ RUSSIA, Respublica Altay] SW. Siberia, Altai, Ongudai District, dry sites and alluvial habitats near the confluence of the rivers Katun and Chuya [50°24’02” N, 86°40’25” E, 780–820 m a.s.l.], 1 Jul 1988, J. Kirschner, cultivated as T 201 ( PRA, no. det. 36675, isotype, and duplicates); Ibidem, cultivated as JŠ 3457 ( PRA, no. det. 36678). – Usť-Ulagan District , range of Kuraiskiy Khrebet, Mt. Aktash , 2600–3050 m, 3–4 Jul 1988, J. Kirschner, cultivated as JŠ 3448 ( PRA, no. det. 36795). – Ongudai District , Khabarovka, between the road and the river Malyy Iľgumeň [ca. 50° 41’ N, 86° 17’ E], 29–30 Jun 1988, J. Kirschner, cultivated as JŠ 3337 ( PRA, no. det. 36793). – 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 T 18 ( PRA, no. det. 35789); Ibidem, cultivated as T 26 ( PRA, no. det. 36787). – Ust-Kan District , along roads at the E. foot of Yabaganskiy Pereval (= Pass)], alt. ca. 1300 m, 27 Jun 1988, J. Kirschner, cultivated as JK 69 ( PRA, no. det. 36785) .

Figures

FIGURE 11. Taraxacum trepidans. A, General habit; B, Achenes (both from PRA, no. det. 35854, holotype).