Taraxacum aquilinum Štěpánek & Kirschner, 2022

Štěpánek, Jan & Kirschner, Jan, 2022, Taraxacum sect. Erythrocarpa in Europe in the Alps and eastwards: A revision of a precursor group of relicts, Phytotaxa 536 (1), pp. 7-52 : 31-32

. Taraxacum aquilinum Štěpánek & Kirschner , sp. nov.

Type:— BULGARIA. Bulgaria , pars australis montium Pirin: in cacumine montis Oreleg (2099 m) [southern part of the Pirin, summit of Mt. Orelyak, Orelek], situ bor.-orient. a pago Pirin, 1982, D. Fišerová, Plantae e seminibus no. JŠ 986 in horto bot. in Průhonice sub no. JŠ 2413 cultae et a. 1988 lectae. ( PRA, no. det. 28655, holotype; isotypes: PRA, no. det. 25902 and duplicates) .

Exsiccates:—Taraxaca Exs., no. 1090–1091.

Etymology:—The Bulgarian name of the type locality, Orelek or Orelyak, is derived from eagle, aquila in Latin.

Diagnosis:—Plantae parvae vel mediocres, Taraxaco dorchocarpo affines, sed acheniis cinnamomeo-brunneis vel laete cinnamomeis, pyramide brevi, crassiuscula cylindica, 0.5–0.9 mm longa, phyllariis involucralibus exterioribus laxe adpressis, erectis usque erectopatentibus, imbricatis, late ovatis usque ad ovato-lanceolatis insignes.

Plants small to medium-sized, usually 7–11 cm tall at anthesis, relatively robust. Plant base probably ± without tunic, light brownish arachnoid. Leaves variably erect-patent, light greyish green, not spotted, glabrous or sparsely arachnoid, usually 6–11 (–15) cm long, 1.5–2.5 cm wide, oblanceolate to narrowly oblanceolate, pinnatisect; terminal segment usually ± small, broadly triangular, broadly rhombic to broadly helmet-shaped, usually 5–15 mm long, 8–22 mm wide, obtusely acute, with distal margin subconvex to subsigmoid to ± straight, entire, basal lobules ± patent to subrecurved, acute, proximal margin straight to subconcave, entire; lateral segments 4–5 (7) pairs, triangular-deltoid to narrowly triangular, usually of a short bird-wing shape, usually 0.8–1.5 cm long, 0.5–1.2 cm wide at the base, ± recurved to subhamate-recurved, acute to obtusely acute, distal margin convex to sigmoid, entire, proximal margin subconcave to concave, or ± straight, entire; interlobes short (terminal segment closely approximated to the next lateral one, otherwise interlobes 1–4 mm long (to 9 mm in the innermost leaves), 2–4 mm wide, entire, in longer interlobes with several thin unequal teeth, margins often raised, not bordered; mid-vein pale to pinkish; petiole 1–2 cm long, ± broadly winged (narrowly so in the innermost leaves), pale or abaxially purplish along mid-vein. Scapes pale greenish, sparsely arachnoid (± more densely below capitulum), 6–9 cm long, subequalling leaves. Capitulum ca. 3 cm wide, subconvex, deep yellow. Involucre ± light olivaceous-green, usually 7–10 mm wide and rounded at base. Outer phyllaries 14–21 (30), loosely appressed, erect to erect-patent, imbricate, the broadest ones ovate to broadly ovate, 6–7.5 mm long, 3–4 mm wide, upper ones ovate-lanceolate to lanceolate, slightly longer (to 9 mm long), the outermost 1–3 ones linear to linear-lanceolate, 1–2 mm wide, the lowermost phyllary often descending 1–2 mm below capitulum, surface of phyllaries of contrasting colours, most of the surface very pale, whitish green, sometimes with a slightly darker middle strip ca. 1 mm wide, the distal 1/3–1/4 of phyllary dark olivaceous-green (black-green when dry), border membranous, (0.05–) 0.1–0.2 mm wide, margin densely ciliate (hairs short, ca. 0.1 mm long, the most distal hairs to 0.3 mm long), apex ± flat, after anthesis phyllary surface evenly darkening; inner phyllaries ca. 12 mm long, of equal width, not corniculate. Outer ligules flat, relatively short, striped dark, reddish olivaceous-grey outside, with apical teeth ±black, inner ligule teeth greyish to purplish. Stigmas light discoloured, greenish yellow or greyish yellow, with a pale pubescence outside. Pollen developed, pollen grains irregular in size. Achenes cinnamon-brown or light greyish cinnamon-brown, 3.8–4.7 mm long, 1.0– 1.2 mm wide, achene body with short subdense broad spinules or squamules in upper 1/4–1/5, otherwise ± smooth, ± gradually (seemingly subabruptly because of the uppermost row of squamules) narrowing into a thicker cylindrical cone (0.5–) 0.7–0.9 mm long, 0.3–0.35 mm wide, sometimes with 1–2 little spinules at the base; beak 8.5–10.5 mm long; pappus yellowish or brownish white, 5.5–6 mm long.— Agamosperm.—Triploid (2n=24, counted by O. Šída from JŠ 2413 under no. 15/93, and by J. Kirschner from JŠ 986, as no. 26/86 and 27/86).

Relationships:— Taraxacum aquilinum , although quite remote from other species, could be confused with T. dorchocarpum in early stages of anthesis. However, T. dorchocarpum has outer phyllaries always loosely appressed, with an evenly dark greyish olivaceous-green surface, usually longer and broader, and achenes without any cinnamon hue, light greyish or light greyish stramineous-brown ( Fig. 16 , 17).

Distribution and ecology:—Mountain summit calcareous cliffs and gravel. A stenotopic endemic, confined to two localities in the Pirin, Mt. Orelyak and Mt. Suchodol ( Fig. 2 ). Its IUCN conservation status is estimated as VU.

Specimens examined:— BULGARIA: Pirin, southern part, summit of Mt. Orelyak , 1982, D. Fišerová, cultivated as JŠ 986, collected in 1985 ( PRA, no. det. 25903), ibidem: cultivated as JŠ 2413, collected in 1988 ( PRA, no. det. 25902).—Pirin, Bansko, Mt. Suchodol, ca. 1400 m, 12 May 1967, F. K. Meyer & J. Meyer 8998 ( JE, no. det. 33832) .

Figures

FIGURE 2. Distribution of species of T. sect. Erythrocarpa. Taraxacum pseudohoppenum (empty circles), T. janchenii (black pentagons), T. aquilinum (stars), T. pudilii (square), T. greuteri (diamonds).

FIGURE 16. Taraxacum aquilinum. A, General habit of a plant on the holotype herbarium sheet (PRA, no. det. 28665). B, Achenes (PRA, no. det. 25903).