Taraxacum serenum 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 serenum

description: . Taraxacum serenum Štěpánek & Kirschner, sp. nov.   
 Type:— Bulgaria australis, montes Pirin, Kazana, 2300–2400 m, 27 Sep 1987, B. Kuzmanov BK8750, cultivated as JŠ 3253, collected in 1989 (PRA, no. det. 35790, holotype; isotype: PRA, no. det. 26113, and duplicates).   
 Etymology:—Clear, bright, tranquil (from Latin, serenus).   
 Exsiccates:— Taraxaca Exs., no. 1339–1345.   
  Diagnosis:—Plantae mediocres vel subrobustae, notis sequentibus bene dignoscendae – foliis patentibus, pallide laete viridibus glabrescentibus, petiolis late alatis pallide viridibus, lobis lateralibus saepissime patentibus deltoideo-triangularibus, phyllariis exterioribus paucis, laete viridibus, in marginem translucente-membranaceam 0.2–0.5 mm latam sensim transeuntibus, acheniis pallide luteo-brunnescentibus vel fulvescentibus, corpore superne irregulariter dense spinuloso, in pyramidem cylindricam, 0.3–0.8 mm longam subabrupte vel subsensim abeunte.    
 Plants medium-sized to subrobust, 8–15 cm tall. Plant base without tunic, without hairs among petiole bases. Petiole broadly winged, pale green, 1.5–3 cm long. Leaves ± numerous, patent (not appressed to the ground), light vivid green, not spotted, ± glabrous, narrowly oblong to narrowly lanceolate, usually (5–) 7–13 × 1.5–3.5 cm, pinnatisect (similar to T. aequilobum or T. urbicola in their shape); terminal segment usually broadly triangular to flat rhombic, acute, apex often lingulate-mucronate, 0.6–2 × 0.8–3 cm, distal margin concave to straight, sometimes subsigmoid, entire, basal lobules patent, acute, proximal margin ± straight to subconcave, entire; lateral segments in (3) 4–6 pairs, patent to subrecurved, usually deltoid, deltoid-triangular or narrowly so, usually 5–20 mm long, 5–13 mm wide at base, distal margin subsigmoid to subconvex, entire, proximal margin ± straight to subconcave, entire; interlobes usually 2–8 × 2– 11 mm, green, not bordered, margin partly raised, sometimes ± plicate, entire or with a single distinct tooth; mid-vein pale greenish. Scapes pale green, glabrous to subglabrous, usually equalling leaves. Capitulum golden yellow, 3.5–4 cm wide, flat. Involucre not pruinose, narrowly rounded to subobconical and 6–8 mm wide at base. Outer phyllaries 12–14, subimbricate, loosely appressed or loosely appressed at base and distally erect-patent to arcuate-patent, usually ovate to lanceolate, often narrowing in an elongated lingulate apex, usually relatively short, reaching 1/3–1/2 of the inner ones, 4–5 (–6) × 2–3 mm, lighter green or medium vivid green, sometimes with a dark middle line, with a gradual transition in a ± translucent membranous border 0.2–0.5 mm wide, margin glabrous or minutely ciliate, sometimes with a tooth or incision; inner phyllaries 11–13 mm long, of ± unequal width. Outer ligules ± flat, striped light grey (or slightly purplish grey) outside, apical teeth black-purple, inner phyllaries canaliculate, their apical teeth reddish to dark yellow. Stigmas discoloured, light grey-yellow or green-yellow, with a dark pubescence outside. Pollen present, pollen grains irregular in size. Achenes light yellowish brown (light yellowish brown, or light greyish brown, or light beigebrown), usually slender, (3.4–) 3.7–4.5 × 0.8–1.0 mm, body with dense, variously irregularly erect to erect-patent, relatively long spinules in upper 1/6–1/4, subabruptly to subgradually narrowing into a cylindrical cone (0.3–) 0.5–0.8 mm long; beak 6–6.5 mm long, pappus white or whitish, 5–5.5 mm long. – Agamosperm. – Fig. 60D, 61, 62.   
 Diagnostic notes:— Taraxacum serenum has a distinctive general habit, with light vivid green leaf colour, ± broadly winged pale green petioles and usually patent, deltoid-triangular lateral segments. Its achenes are light brownish, often with a beige hue, with a short cylindrical cone and an irregularly spinulose achene body. The most similar species is T. tetricum having longer, more deeply brown achenes with a longer cone, and outer phyllaries with a sharply delimited border.   
 Distribution and habitat:—Known from subalpine and alpine belts of Pirin and Rila, from 1500 to 2500 m. It grows in wet grasslands, frequently along paths. Its IUCN conservation status is estimated as NT.   
 Specimens examined:— BULGARIA. Pirin, 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. 26109); Ibidem, JŠ 6309 (PRA, no. det. 26111); Ibidem, JŠ 6551 (PRA, no. det. 26110). – Bansko, valley of Banderica, Banderiški ezera, near lake Dalgoto ezero, 2300–2350 m, 14 Aug 1990, J. Štěpánek, cultivated as JŠ 4847 (PRA, no. det. 26108). – Bansko, glacial cirque of Popovoezeren cirkus, slopes below the pass of Samodivska porta, ca. 2350 m, 41° 42–43’ N, 23° 30’ E, 8 Aug 1997, J. Štěpánek, cultivated as JŠ 6480 (PRA, no. det. 26107); Ibidem, JŠ 6479 (PRA, no. det. 26106); Ibidem, JŠ 6478 (PRA, no. det. 26104). – Bansko, valley of Demjanica, ca. 1 km below the Julenski skok [waterfall], ca. 1500 m, 41° 47-48’ N, 23° 28-29’ E, 8 Aug 1997, J. Štěpánek, cultivated as JŠ 6471 (PRA, no. det. 26105). – Bansko, Banderica valley, valley of the brook of Vichrenska voda, above the Vichren Chalet, ca. 2225 m, 12 Aug 1990, J. Štěpánek, cultivated as JŠ 4304 (PRA, no. det. 26103). – Bansko, glacial cirque of Vasilaški cirkus, along a path near the lake of Todorino ezero, ca. 2500 m, 14 Aug 1990, J. Štěpánek, cultivated as JŠ 4535 (PRA, no. det. 26102). – Bansko, Demjanica valley, along the Demjanica river, near Demjaniška polana, above the Demjaniški skok [waterfall], ca. 1800–1850 m, ca. 41° 45’ N, 23° 28–29’ E, 8 Aug 1997, J. Štěpánek, cultivated as JŠ 9303 (PRA, no. det. 26101); Ibidem, JŠ 9305 (PRA, no. det. 26119). – Bansko, valley of Vichrenska voda, above the alpine chalet of Vichren, ca. 2300 m, 12 Aug 1990, J. Štěpánek, cultivated as JŠ 4537 (PRA, no. det. 26100). – Bansko, valley of Vichrenska voda, above the alpine chalet of Vichren, ca. 2400 m, 12 Aug 1990, J. Štěpánek, cultivated as JŠ 4869 (PRA, no. det. 26099). – 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), 2250–2300 m, 9 Aug 1997, J. Štěpánek, cultivated as JŠ 6308/C (PRA, no. det. 26098); Ibidem, JŠ 9337 (PRA, no. det. 26120); Ibidem, JŠ 9335 (PRA, no. det. 26116); Ibidem, JŠ 9333 (PRA, no. det. 26180). – Bansko, Banderica valley, a valley between Mt. Graniten (2669 m) and Chvojnati vrch (2635 m), above Chvojnato ezero [lake], 2250–2350 m, 12 Aug 1990, J. Štěpánek, cultivated as JŠ 4870 (PRA, no. det. 26097). – Bansko, valley of Vichrenska voda, above the alpine chalet of Vichren, ca. 2250 m, 12 Aug 1990, J. Štěpánek, cultivated as JŠ 4886 (PRA, no. det. 26096). – Bansko, a pine woods above the Banderica Chalet, ca. 1900 m, 15 Aug 1997, J. Štěpánek, cultivated as JŠ 4524 (PRA, no. det. 26118). – Bansko, Malak Kazan, at the NW. foot of Mt. Vichren, limestone, 2100 m, 13 Aug 1990, J. Štěpánek, cultivated as JŠ 4539 (PRA, no. det. 26115). – Bansko, gravelly sites along the Banderica Brook, near the Banderica Chalet, ca. 1800 m, 11 Aug 1990, J. Štěpánek, cultivated as JŠ 4555 (PRA, no. det. 26112). – The Rila, Samokov, Borovec, near the Musala Chalet, ca. 2200–2300 m, 9 Aug 1990, J. Štěpánek & B. Kuzmanov, cultivated as JŠ 4815 (PRA, no. det. 26114). – Govedarci, valley of Maljovica River, 1–1.5 km S. of the Maljovica Chalet, 2200– 2250 m, 42° 11–12’ N, ca. 23° 25’ E, 10 Aug 1997, J. Štěpánek, cultivated as JŠ 9354 (PRA, no. det. 26121); Ibidem, JŠ 9353 (PRA, no. det. 26117). – Less certain identification: Pirin, below the Demjanica Chalet, 2200 m, 8 Aug 1997, B. Trávníček, cultivated as JK 4340 (PRA, no. det. 35951). – Rila, Govedarci, valley of Maljovica River, ca. 1 km above “Kompleks Maljovica”, ca. 1800 m, 42° 12’ N, ca. 23° 25’ E, 10 Aug 1997, J. Štěpánek, cultivated as JŠ 9349 (PRA, no. det. 26122). – Rila, the Musala Chalet, 12 Jul 1976, R. Doll [as T. mattmarkense] (JE, no. det. 19262).
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 page 106, DOI: 10.11646/phytotaxa.569.1.1, http://zenodo.org/record/7235182