Taraxacum lacusculorum 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

14. Taraxacum lacusculorum Kirschner & Štěpánek , sp. nov.

Type:—[ CHINA, Xinjiang] Xinjiang, Tian Shan, in pratis montanis ad lacum Tian chi ( Tian chi Lake ), May 1999, P. Sekerka, Zhang Dao Yuan & V. Huml, cultivated as JŠ 7387 ( PRA, no. det. 35848, holotype; isotypes: PRA, no. det. 36686, isotype) .

Etymology:—Little lake (lacusculus).

Diagnosis:—Plantae insignes foliis glauco-viridibus, petiolis purpurascentibus, phyllariis involucralibus exterioribus paucis, ovatis, anguste distincte albomarginatis, stigmatibus obscuris, necnon acheniis rubro-brunneis, angustis, corpore superne conspicue spinulosis, in pyramidem angustam, plerumque 1.1–1.2 mm longam sensim transeunte.

Plants small, usually to 8–10 cm tall. Petiole narrow, narrowly winged to unwinged, purplish to purple, sparsely arachnoid; plant base with whitish hairs, tunic developed. Leaves greyish green to glaucous-green, usually sparsely arachnoid, outer leaves sometimes glabrescent, ± narrowly oblanceolate in outline, usually 4–7 × 1.0–1.5 (–1.8) cm, pinnatisect, lateral segments 3–4 (–5) pairs, ± patent, sometimes subrecurved, narrowly oblong-triangular to deltoidtriangular, distal margin straight to subconvex, usually entire, rarely with a single basal tooth, proximal margin straight to subconvex, entire, apex subobtuse to acute; terminal segment triangular to ± helmet-shaped or tripartite, straight to ± convex in triangular segments, concave in tripartite ones, entire, basal lobules patent; interlobes variable, often short and entire, very often distinct, broad, sparsely denticulate; mid-vein usually suffused brownish-purplish. Scapes purplish green, sparsely arachnoid, equalling to slightly overtopping leaves. Capitulum yellow, to 3 cm wide. Involucre greyish green, 7–9 mm wide and rounded at base. Outer phyllaries 7–10, appressed or loosely appressed, ± not imbricate, ovate, 5–6.5 × (2.2–) 2.9–3.4 mm, surface greyish olivaceous-green, border narrow, distinct, whitishmembranous to whitish, 0.3–0.4 (–0.5) mm wide, margin cilate, apex dark green to blackish green, suffused purple, ± flat; inner phyllaries 11–13 mm long at anthesis, apex flat. Outer ligules flat, striped grey purplish outside, inner ligule teeth light (dirty) purplish. Stigmas dark discoloured, greenish, with a dark pubescence outside. Pollen present, pollen grains irregular in size. Achenes red-brown, (3.5–) 3.9–4.2 × 0.7–0.8 mm, body with very distinct subsparse acuminate erect-patent spinules to 0.3 mm long in upper 1/3, gradually narrowing into cylindrical cone (0.9–) 1.1–1.2 × 0.2 mm; beak 7 mm long, pappus ca. 5.5 mm long, ± white. –Agamosperm. – Fig. 16 .

Diagnostic notes:—Short, ovate, often loosely appressed outer phyllaries, glaucous-green leaves, and slender, red-brown achenes with a long, thin cone are diagnostic. It might be compared with T. babcockii but the thin achenes of T. lacusculorum with a long thin cylindrical cone are diagnostic.

Distribution and habitat:—It occurs in the western Xinjiang, China. The known habitats of T. lacusculorum include stony substeppe slopes and dry meadows, at about 1900–2000 m.

Specimens examined:—[ CHINA, Xinjiang] W. Xinjiang, the Tian Shan [Fukang vicinity, Bogda Shan, ca. 1930 m a.s.l., ca. 43°54’ N, 88°07’ 23” E], mountain meadows near the Tianchi Lake , May 1999, P. Sekerka, Zhang Dao Yuan & V. Huml, cultivated as JŠ 7387 ( PRA, with duplicates) .

Figures

FIGURE 16. Taraxacum lacusculorum. A, General habit; B, Achenes (both from PRA, no. det. 35848, holotype), the colour is more reddish when viewed in daylight.