Taraxacum xiphodon Kirschner & Štěpánek, 2025

Kirschner, Jan, Štěpánek, Jan & Buryy, Vladimir V., 2025, Towards a revision of Taraxacum sect. Borealia (Compositae, Crepidinae) in Siberia and the continental Far East, with special reference to the dandelions of the Altai and Kamchatka, Phytotaxa 679 (1), pp. 1-147 : 82-85

32. Taraxacum xiphodon Kirschner & Štěpánek , sp. nov.

Type:—[ RUSSIA, Altai Republic] USSR, Sibiria austro-occid., montes Altaj, distr. Ongudaj , in pratis ad viam publicam in clausa mont. Seminskij Pereval dicta, ca. 1760 m, 27 Jun 1988 , J. Kirschner , cultivated as T 162 ( PRA, no. det. 35851, holotype) .

Etymology:—Sword-like teeth.

Diagnosis:—Plantae robustae foliis obscure viridibus arachnoideis interlobiis plerumque maculatis, phyllariis involucralibus exterioribus variabiliter spectantibus, saepissime patentibus, arcuato-patentibus vel arcuato-recurvis, lineari-lanceolatis longissimis, apice cornutis, acheniis brevibus, corpore superne subdense spinuloso, in pyramidem subconicam brevem subsensim transeunte.

Plants robust, to ca. 20 cm tall. Petiole brownish purple, arachnoid to densely arachnoid, winged (unwinged in the innermost leaves), plant base without tunic. Leaves ± dark green to slightly greyish green, arachnoid, mostly along mid-vein, with “dirty” dark purple mid-vein, oblong in outline, 7–11 × 1.5–3.0 cm, usually pinnatisect to pinnatipartite; terminal segment relatively short, trilobed with acute tip and patent acute basal lobules, margins entire; lateral segments usually in 4–5 pairs, patent, narrowly deltoid-triangular to narrowly triangular, distal margin straight to concave, usually with several little teeth, proximal margin ± straight, entire, apex often acuminate; interlobes distinct, entire or irregularly denticulate, often blotched or spotted brown-purple; in each leaf rosette usually also undivided (dentate) or shallowly lobed leaves. Scapes usually brownish-purplish, arachnoid, overtopping inflorescence, often growing from outside the leaf rosette. Capitulum yellow, ca. 3.5 cm wide. Involucre blackish olivaceous-green, ca. 9–10 mm wide and rounded to subtruncate at base. Outer phyllaries 13–16, ± patent, arcuate-patent or arcuate-recurved, lanceolate to linear-lanceolate, usually (8–) 9–11 (–12) × (2.0–) 2.3–3.0 (–3.7) mm, abaxial surface evenly blackish olivaceous-green, darker distally, border very narrow, whitish-membranous, 0.1–0.2 mm wide, adaxial surface deep olivaceous-green, margin glabrous, apex corniculate in early capitula, distinctly horned in later ones, horns black-purple, obtuse, usually to 1 mm long; inner phyllaries 14–19 mm long, blackish olivaceous-green, usually corniculate. Outer ligules narrow, canaliculate, striped greyish purple outside, teeth black-purple, inner ligule teeth purplish. Stigmas greenish, with dark grey pubescence outside. Pollen present, pollen grains irregular in size. Achenes light greyish stramineous-brown, relatively small, usually 2.9–3.2 × 0.8–0.9 mm, body ± subdensely covered with short thin spinules in upper 1/4, subgradually narrowing into a subconical cone (0.4–) 0.5 (–0.6) mm long, ca. 0.35–0.40 mm thick at base, ca. 0.25 mm distally; beak thin, 8–9 mm long, pappus white, ca. 5 mm long. – Agamospermous. – Fig. 4G , 53 , 54 .

Diagnostic notes:—This species, with robust growth and narrow, long, variously patent to arcuate-recurved outer phyllaries, and small achenes, is rather reminiscent of T. sect. Taraxacum ( T. officinale s. lat.) and may be considered as intermediate between the two sections. However, the outer phyllaries with conspicuous black-purple horns in later capitula and the short, subconical to ± conical cone point to T. sect. Borealia. The broadly winged petiole of middle leaves, patent, narrowly deltoid-triangular lateral segments, blotched or spotted interlobes also characterize T. xiphodon .

Distribution:— Taraxacum xiphodon is known from a single macrolocality in the pass of Seminskiy Pereval, Ongudai District, Altai Republic. In all likelihood, however, it is more widely distributed in the northern Altai.

Specimens examined:—[ RUSSIA, Altai Republic] the Altai Mts., Ongudai District, meadows in the vicinity of Seminskiy Pereval [pass], ca. 1760 m, 27 Jun 1988, J. Kirschner, cultivated as T 162 ( PRA, no. det. 36742, isotype) .

Species characterized by numerous, linear-lanceolate outer phyllaries with conspicuous horns, and a very narrow leaf shape

Figures

FIGURE 4. Details of involucres of Taraxacum species from the Altai, in alphabetic order. A, T. peracre (PRA, T 55); B, T. perdecorum (PRA, no. det. 35992); C, T. peschkovae (PRA, no. det. 35855); D, T. seminudum (PRA, JŠ 2597); E, T. tortisquameum (PRA, no. det. 35983); F, T. xanthellum (PRA, T 173); G, T. xiphodon (PRA, T 162). Scale bars: D = 2 mm; A–C, E–G = 5 mm.

FIGURE 53. Taraxacum xiphodon. The holotype. Photo M. Hladík.

FIGURE 54. Taraxacum xiphodon. A, general habit (PRA, no. det. 35851, holotype); B, achenes (PRA, from specimens cultivated as T 162).