Taraxacum argutisectum 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

20. Taraxacum argutisectum Kirschner & Štěpánek , sp. nov.

Type:—[ RUSSIA, Respublika Altay, district of Shebalino] montes Altaj (bor.), in decl. substepposis prope pagum Aktjol [Актёл, Aktyol, ca. 51°31’ N, 85°40 E], 25 Jun 1988, J. Kirschner, cultivated from achenes of JŠ 3322 as T 207 ( PRA, no. det. 35856, holotype; isotype: PRA, no. det. 36684) .

Etymology:—Dissected, notched.

Diagnosis:—Plantae mediocres, foliis ad 12 cm longis, segmentis lateralibus numerosis, recurvis, peranguste triangularibus acuminatis dentatis, phyllariis involucralibus exterioribus numerosis, anguste lanceolatis usque ovato-lanceolatis, olivaceo-viridibus, marginibus distinctis albo-membranaceis, plerumque 0.3–0.4 mm latis, ciliatis, acheniis pallide griseo-brunneo-stramineis, corpore superne dense spinuloso, in pyramidem subconicam, 0.9–1.0 mm longam abrupte transeunte, necnon rostro longissimo.

Plants medium-sized, usually to 14 cm tall. Petiole narrowly winged, usually purplish, arachnoid; plant base with whitish hairs, tunic ± developed. Leaves ± deep green to dark green, sparsely arachnoid, often narrowly bordered dark purple or with brown-purple spots on interlobes, narrowly oblanceolate in outline, usually 7–12 × 2.3–3.2 cm, deeply pinnatisect, with 5–7 (8) pairs of subrecurved to recurved, narrowly triangular to linear-triangular, acuminate lateral segments, distal margin ± straight, with several perpendicular, filiform or acuminate long teeth, proximal margin ± straight, most often with a few filiform teeth; terminal segment triangular or triangular-deltoid, entire or with a tooth and an incision, basal lobules patent, proximal margin ± entire; interlobes usually ± short, usually with acuminate lobules and/or filiform teeth, rarely subentire; mid-vein purplish. Scapes brownish green and usually suffused purplish, arachnoid, ± equalling or slightly overtopping leaves. Capitulum yellow, convex, ca 3 cm wide. Involucre dark olivaceous-green, ca.8–9 (–10) mm wide and rounded at base. Outer phyllaries 13–17, not imbricate, erect, erect-patent or patent, narrowly lanceolate to ovate-lanceolate, usually (6–) 7–8.5 (–9) × 2.5–3.7 mm, surface light olivaceous-green, rarely proximally yellowish green with a visible darker middle part, border distinctly developed, membranous to whitish-membranous, (0.3–) 0.4–0.5 mm wide, margin long ciliate distally, its distal part suffused pale reddish, apex ± flat; inner phyllaries ca. 14 mm long, flat. Outer ligules flat, striped grey outside, inner ligule teeth dirty yellow. Stigmas light greyish yellow-green, with a dark grey pubescence outside. Pollen present, pollen grains irregular in size. Achenes light greyish stramineous-brown, (3.5–) 3.7–4.0 × 0.9–1.0 mm, body with ± dense, thick, erect-patent spinules in upper 1/3, abruptly narrowing into a subconical cone (0.7–) 0.9–1.0 mm long, ca. 0.30–0.35 mm thick at base, 0.2–0.25 mm distally, beak 10–11 mm long, pappus yellowish white, 5.5–6 mm long. –Agamosperm. – Fig. 22 .

Diagnostic notes:— Taraxacum argutisectum , in the features of outer phyllaries and in its achene colour, approaches T. angarense and T. vadosum . Its numerous, acuminate, recurved, filiform-dentate lateral segments of leaves are so different from those of the other members of this section that the material leaves little doubts about the separate status of this species. Moreover, T. vadosum has achenes light brown or light fulvous-brown to light cinnamon-brown, and T. angarense is characterized by lateral segments patent and outer phyllaries with horns. Another similar species, T. ovatum , differs in having a shorter beak and brown achenes.

Distribution and habitat:—This species was collected at a single macrolocality, at substeppe slopes in the vicinity of the village of Aktyol in the northern part of the Altai Republic.

Specimens examined:—[ RUSSIA, Respublika Altay, district of Shebalino] the northern Altai, substeppe slopes in the vicinity of Aktyol [ca. 51°31’ N, 85°40’ E], 25 Jun 1988, J. Kirschner, cultivated as T 207 ( PRA, no. det. 36684, with duplicates); Ibidem, T 67 ( PRA, no. det. 36950) .

Figures

FIGURE 22. Taraxacum argutisectum. A, General habit; B, Achenes (both A and B from PRA, no. det. 35856); C, A SEM picture of an achene from the cultivation JŠ 3322. Scale bars: B, C = 1 mm; A = 2 cm.