Taraxacum tephroleucum Štěpánek & Kirschner, 2022

Štěpánek, Jan & Kirschner, Jan, 2022, A hotspot of endemism: Oreophytic Taraxacum species (Compositae, Crepidinae) in the mountains of Bulgaria, Phytotaxa 569 (1), pp. 1-139 : 69-72

9. Taraxacum tephroleucum Štěpánek & Kirschner , sp. nov.

Type:— Bulgaria, montes Rila , opp. Samokov , pagus Borovec , Musalenski Ezera , ad casam alpinam ‘ Ledenoto Ezero’ in ripa lacus VII. (= Ledenoto Ezero) sub monte Musala (2925 m), ca. 2715 m, 9 Aug 1990, J. Štěpánek, cultivated as JŠ 4496, collected in 1991 ( PRA, no. det. 36034, holotype; isotype: PRA, no. det. 36036, and duplicates) .

Etymology:—Greyish white, whitish light grey (colour of achenes, derived from τεφροϛ, ash grey, and λευκοϛ, white, pale).

Diagnosis:—Species sectionis Bulgaricorum marginalis, notabilis acheniis pallide albo-cinerascentibus, perpallide fulvo-albidis vel eburneis, corpore superne subsparse breviter spinuloso-squamuloso, in pyramidem late conicam sensim abeunte, foliis sparse minute maculatis, subter pilis sparsissimis multicellularibus versicoloribus septis transversalibus ferrugineis vel brunneo-coloratis praeditis, phyllariis involucralibus exterioribus imbricatis, adpressis vel laxe adpressis, atro-viridibus, marginibus pallidioribus angustissimis.

Plants small to ± medium-sized, ± slender, 7–10 cm tall. Plant base with an imperfectly developed tunic, with sparse brownish hairs among petiole bases. Petiole winged to very broadly winged, pale, 1.5–2.5 cm long. Leaves patent to prostrate, most of them appressed to the ground, light greyish-green, with very sparse minute brown-purple spots above, abaxially glabrous, adaxially with very sparse, slightly brownish, ± straight multicellular hairs along the midvein (slightly brownish cell walls and darker brownish coloration of walls connecting cell pairs make an impression of transversally striate hairs), narrowly oblong, linear-oblanceolate or narrowly elliptical in outline, usually 5–9 (–11) × 1.2–2 cm, pinnatisect to pinnatipartite; terminal segment relatively small, usually broadly triangular or flat rhombic, sometimes trilobed, acute, distmal margin concave or sigmoid, less often ± straight, entire (in inner leaves, with an elongated segment, there is a constriction with 1–2 teeth in the middle), basal lobules usually patent to hamatesubrecurved, sometimes asymmetrically curved upwards, proximal margin concave to ± straight, entire; lateral segments in (3) 4–5 pairs, narrowly triangular or triangular, usually 4–11 mm long, 5–9 mm wide at base, or often bird-wing-like (from a broad basal part ± abruptly narrowed in a narrow distal part), subrecurved to hamate-subrecurved, acute to acuminate, distal margin sigmoid, ± straight or subconvex, entire or with one or a few narrow teeth, proximal margin subconcave to ± straight, entire; interlobes ± long, usually 2–7 × 2.5–4 mm, green, faintly bordered grey-purple, margin sometimes ± raised, entire or with 1–2 narrow little teeth; mid-vein pale. Scapes glabrous to subglabrous, pale greenish, overtopping leaves. Capitulum yellow, ± flat, 3–3.5 cm wide. Involucre slightly pruinose, 7–8 mm wide and ± rounded at base. Outer phyllaries 13–15, ± imbricate, appressed to loosely appressed, variably long, the outermost ones ovate to broadly ovate, 4.5–5.5 mm long, the inner of them to ca. 7–8.5 mm long, 2.5–3.5 mm wide, evenly black-green (black when dry), with an abrupt transition in a narrow, white to dirty white border 0.05–0.1 mm wide, margin ± densely ciliate, apex flat; inner phyllaries 12–14 mm long, of ± equal width. Outer ligules narrow, flat, striped dark olivaceous-grey outside, apical teeth grey-black, inner ligules canaliculate, their apical teeth greyish or dirty dark yellow. Stigmas long, dark discoloured, grey-green with dark pubescence outside. Pollen present, pollen grains irregular in size. Achenes very pale, slightly greyish white to very light beige or ivory white, 4.3–5.1 × 1.1–1.2 mm, body oblong-turbinate, with subsparse short thin spinules, little squamules or comb-like squamules in upper 1/5, ± gradually narrowing into a broad conical cone 0.7–1.0 mm long; beak 5.5–6 mm, pappus whitish, ca. 6.5 mm long. – Agamosperm. – Fig. 36, 37A.

Diagnostic notes:— Taraxacum tephroleucum deviates from the common pattern of T. sect. Bulgarica in relatively narrow leaves (similar to those of T. heleonastes G. E. Hagl. of T. sect. Palustria ), perhaps approaching those of T. sect. Crocea. It is a distinctive species characterized by almost white achenes with a short, conical cone, the peculiar leaf indumentum (with scattered hairs having brown connecting cell walls), and a dark involucre with outer phyllaries very narrowly bordered.

Distribution and habitat:—Probably confined to the Rila, Bulgaria, at ca. 2700–2900 m. It grows in stony alpine grasslands. Its IUCN conservation status is estimated as VU.

Specimens examined:— BULGARIA. Samokov , the Rila Mts. , Borovec, summit of Mt. Musala, ca. 2920 m, 9 Aug 1990, J. Štěpánek, cultivated as JŠ 4502 ( PRA, no. det. 36038). – Rila, Borovec, Muslaenski Ezera (lakes), near the chalet of Ledeneto Ezero, along the shore of Lake VII (Ledenoto Ezero), ca. 2715 m, 9 Aug 1990, J. Štěpánek, cultivated as JŠ 4498 ( PRA, no. det. 36055) .