Taraxacum circense Stepanek & Kirschner 2022, sp. nov.
Creators: name: Štěpánek, Jan
name: Kirschner, Jan
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Asterales
Asteraceae
Taraxacum
Taraxacum circense

description: 5. Taraxacum circense Štěpánek & Kirschner, sp. nov.   
 Type:— Bulgaria, montes Pirin, opp. Bansko, in parte inferiore circi glacialis Goljam Kazan ad decl. boreal. montis Vichren (2914 m), solo calcareo, ca. 2400 m, 15 Aug 1990, J. Štěpánek, cultivated as JŠ 4525, collected in 1991 (PRA, no. det. 35738, holotype; isotype: PRA, no. det. 26148, and duplicates).   
 Etymology:—Referring to cirque, in this case, a glacial cirque (circensis, derived from circus, a Roman stadium, see Gaffiot 1934).   
 Exsiccates:— Taraxaca Exs., no. 1275–1277.   
  Diagnosis:—Species spectabilis, conspicue seclusa, differt phyllariis exterioribus paucioribus, laxe adpressis, marginibus pallidis angustis, conspicue ciliatis, foliis gramineo-viridibus paulo cinerascentibus, inconspicue sparsissime minute maculatis, acheniis longis tenuibusque pallide fulvescenti-brunnescentibus, corpore in pyramidem subconicam vel conicam, 0.3–0.6 mm longam sensim transeunte.    
Plants small to medium-sized, 8–15 cm tall, subcompact. Plant base without tunic, sparsely brownish to dirty whitish hairy among petiole bases. Petiole pale, ± broadly to very narrowly winged, 2–3 cm long. Leaves variously erect-patent to subpatent, greyish green, inconspicuously spotted purplish (spots more distinct on outer leaves, mainly on marginal parts of several proximal leaf segments), almost glabrous, oblanceolate, narrowly oblanceolate, narrowly elliptical to spatulate, usually 5–10 × 1.5–2.5 cm, pinnatisect to pinnatipartite; terminal segment usually dominant, helmet-shaped, triangular or broadly so, usually 1–2.5 × 1.2–2.5 cm, acute, distal margin convex to subsigmoid, entire or with an asymmetrical shallow obtuse incision, basal lobules arcuate-recurved, acuminate, proximal margin usually concave, entire, with a raised margin near the base; lateral segments in 3–4 pairs, often hamate-recurved, deltoid-triangular to triangular, usually 5–9 mm long, 5–8 mm wide at base, distal margin convex to subsigmoid, entire or with a single thin tooth, proximal margin concave to ± straight, ± entire; interlobes ± short, usually 3–8 × 3–5 mm (distal interlobes of inner leaves to 10 mm wide), occasionally sparsely spotted, margin indistinctly bordered brown-purple, usually entire, sometimes with a single filiform tooth, or sparsely minutely denticulate, margin often raised; mid-vein pale or slightly suffused brown-purple. Scapes pale greenish, getting purplish after anthesis, very sparsely arachnoid, equalling or overtopping leaves. Capitulum yellow, 2.5–4 cm wide, ± flat. Involucre slightly pruinose, ca. 7–8 mm wide and very narrowly rounded at base. Outer phyllaries 11–14, loosely appressed, subimbricate, relatively short, reaching 1/3–1/5 of the inner ones, lanceolate to ovate-lanceolate, usually (4–) 5–6 × 2–3 mm, surface evenly, medium dark olivaceousgreen, distally and along margins often suffused brown-purple, with an abrupt transition in a narrow membranous border 0.1–0.2 mm wide, margin conspicuously ciliate (hairs to 0.3 mm), apex flat; inner phyllaries ca. 13 mm long, of ± equal width. Outer ligules flat, narrow, striped purplish grey-green outside, apical teeth black to purple-black, inner ligules canaliculate, their apical teeth dark yellow to dirty yellow. Stigmas long, light discoloured, greyish light yellowgreen, about a half of the stigmatic pubescence have distal part black. Pollen abundant, pollen grains irregular in size. Achenes light beige-brown (very light brown with an orange and grey hue), long and slender, 4.6–5.4 × 0.9–1.0 mm, body with medium dense to subsparse short squamules and spinules, gradually narrowing into a subconical to conical cone (0.3–) 0.4–0.6 mm long, ca. 0.5–0.6 mm thick at base, ca. 0.4 mm distally, with a few little basal spinules; beak 4–6 (–7) mm long, pappus whitish, 6–7 mm long. – Agamosperm. – Fig. 46B, 47.  
 Diagnostic notes:— Taraxacum circense, a species very marginal within T. sect. Bulgarica, is characterized by indistinctly and marginally spotted leaves, outer phyllaries not numerous, short, very narrowly bordered, and achenes very light beige-brown. In the general habit and the size (and mostly also the shape) of achenes, it approaches the group of T. pirinicum. Of this group, T. leopardinum has conspicuously, richly spotted leaves, longer cone (0.8–1.1 mm) and outer phyllaries with a gradual transition in a pale border ca. 0.5 mm wide. Taraxacum abnorme differs from T. circense in having a distinct, whitish-membranous, 0.2–0.5 mm wide border to outer phyllaries, and T. pirinicum is distinguished by its medium deep pure brown or slightly castaneous-brown achenes. It should be added that T. circense seems to be relativly variable, which may point to its possible multiclonality.   
 Distribution and habitat:—The most frequent occurrence of T. circense was recorded from the Rila and Pirin, and it also proved to occur in the Stara Planina, between (1800–) 2200–2600 m. It grows on slopes with stabilized scree with boulders, sparse alpine grasslands, and at slightly disturbes sites in the vicinity of natural ones. Its IUCN conservation status is estimated as NT.   
 Specimens examined:— BULGARIA. Pirin, Bansko, lower part of glacial cirque of Goljam Kazan on NE. slopes of Mt. Vichren, ca. 2400 m, 15 Aug 1990, J. Štěpánek, cultivated as JŠ 4525 (PRA, no. det. 26149, 36059, 36056); Ibidem, JŠ 4525 (PRA, no. det. 26148); Ibidem, 2400–2600 m, JŠ 4861 (PRA, no. det. 26173). – Bansko, valley of Banderica, eastern slopes in the valley of Vichrenska voda, above the alpine chalet of Vichren, 2200–2400 m, 41° 45–46’ N, 23° 24–25’ E, 9 Aug 1997, J. Štěpánek, J. Kirschner & B. Trávníček, cultivated as JŠ 6309 (PRA, no. det. 26147). – Bansko, Malak Kazan, at the NE. foot of Mt. Vichren, limestone, ca. 2100 m, 13 Aug 1990, J. Štěpánek, cultivated as JŠ 4539 (PRA, no. det. 26146). – Bansko, Mt. Vichren, near the shore of the upper lake of the Vlachinski ezera, at the eastern foot of the Gredaro Ridge, ca. 1.5 km W. of Mt. Chvojnati vrch (2635 m), ca. 2250-2300 m, ca. 41° 45’ N, 23° 23’ E, 9 Aug 1997, J. Štěpánek, cultivated as JŠ 6552 (PRA, no. det. 36081). – Bansko, Banderica valley, between Vichrenski preslap [pass] and the southern foot of Mt. Vichren (2914 m), ca. 2550–2600 m, 41° 45–46’ N, ca. 23° 24’ E, 9 Aug 1997, J. Štěpánek, J. Kirschner & B. Trávníček, cultivated as JŠ 6299 (PRA, no. det. 36060); Ibidem, JŠ 9316 (PRA, no. det. 36058); Ibidem, JŠ 9312 (PRA, no. det. 36003). – Bansko, glacial cirque of Vasilaški Cirkus, upper lake of Todorino ezero, ca. 2500 m, 14 Aug 1990, J. Štěpánek, cultivated as JŠ 4535 (PRA, no. det. 36057). – Bansko, Premkata Pass between Mt. Vichren and Mt. Kutelo I, limestone, 2700-2750 m, 13 Aug 1990, J. Štěpánek, cultivated as JŠ 4536 (PRA, no. det. 36064). – Pirin Banderica Valley, 2270 m, 2 Aug 2000, Z. Szeląg (PRA, no. det. 36062). – Bansko, glacial cirque of Goljam Kazan on NE. slopes of Mt. Vichren, ca. 2400–2600 m, 15 Aug 1990, J. Štěpánek, cultivated as JŠ 4526 (PRA, no. det. 36005). – Rila, Samokov, Borovec, Musalenski ezera, E. slopes ca. 100 m above the Musala Chalet, ca. 2400 m, 9 Aug 1990, J. Štěpánek, cultivated as JŠ 4827 (PRA, no. det. 36079); Ibidem, JŠ 4820 (PRA, no. det. 36082). – Samokov, Borovec, Musalenski ezera, lake shore ca. 500 m SW. of the Musala Chalet, ca. 2450 m, 9 Aug 1990, J. Štěpánek, cultivated as JŠ 4282 (PRA, no. det. 36077); Ibidem, JŠ 4503 (PRA, no. det. 36073); Ibidem, JŠ 4812 (PRA, no. det. 36067). – Samokov, Borovec, Musalenski ezera, along a brook below the Musala Chalet, 2200–2300 m, 9 Aug 1990, J. Štěpánek, cultivated as JŠ 4822 (PRA, no. det. 36075). – Rila, near the alpine chalet of Rybnie ezera, ca. 2000 m, 13 Aug 1986, B. Kuzmanov, cultivated as JŠ 3255 (PRA, no. det. 36071). – Samokov, Borovec, near the Musala Chalet, ca. 2390 m, 9 Aug 1990, J. Štěpánek & B. Kuzmanov (PRA, no. det. 36078). – Stara Planina, Zlatiško-Tetevenska planina, Teteven, village of Ribarica, Mt. Vežen (2198 m), a ridge between Mt. Kamenica and the pass of Ribariški Prohod, ca. 1800–1950 m, ca. 42° 45’ N, ca. 24° 26–27’ E, 20 Jul 1998, J. Štěpánek, R. Bělohlávková, V. D. Vladimirov & D. Petkova, cultivated as JŠ 6781 (PRA, no. det. 36080).   
 Note:—There is a material that could have been assigned to T. circense only with a certain probability. It comes from the Rila (Ledenoto ezero, PRA, no. det. 36069; Maljovica Chalet, PRA, no. det. 36061; Komplex Maljovica, PRA, no. det. 36065; Maljovica Chalet, PRA, no. det. 36063), and the Pirin (Chvojnato ezero, PRA, no. det. 36042). We refer to this material collectively as the T. circense group, and leave it for further examination.
description: Published as part of Štěpánek, Jan & Kirschner, Jan, 2022, A hotspot of endemism: Oreophytic Taraxacum species (Compositae, Crepidinae) in the mountains of Bulgaria, pp. 1-139 in Phytotaxa 569 (1) on pages 84-85, DOI: 10.11646/phytotaxa.569.1.1, http://zenodo.org/record/7235182