Taraxacum fragile 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 : 101-103

0. Taraxacum fragile Štěpánek & Kirschner , sp. nov.

Type:— Bulgaria, montes Pirin , opp. Bansko , vallis flum. Demjanica , locis glareosis sub Picea in alluvionibus vetustis flum. Demjanica , haud procul (supra = situ merid.) a casa alpina Demjanica (1895 m), ca. 9.5 km situ merid. ab opp. Bansko, ca. 1850–1900 m, ca. 41° 45’ N, 23° 28’ E, 8 Aug 1997, J. Štěpánek, cultivated as JŠ 9289, collected in 2012 ( PRA, no. det. 36074, holotype; isotype: PRA, no. det. 36076, and duplicates) .

Etymology:—Unstable, fragile, unsteady (from Latin, fragilis).

Diagnosis:—Species ax affinitate T. pseudoalpestri sed differt acheniis pallide stramineo-brunnescentibus, pyramide cylindrica, saepissime 0.8–1.4 mm longa, phyllariis involucralibus exterioribus paucioribus, et foliis pallide viridibus glaberrimis, subfragilibus lactuciformibus.

Plants medium-sized to relatively large, 15–20 cm tall, not robust. Plant base without tunic, with sparse brownish hairs among petiole bases. Petiole pale green, winged to broadly winged, 3–7 cm long. Leaves variously erect-patent, glabrous to almost glabrous, yellowish green, shining, lettuce-like crisp, not spotted, oblanceolate to narrowly so in outline, usually 7–18 × 3–5 cm, pinnatipartite to pinnatisect; terminal segment broadly triangular to broadly helmetshaped, usually 1.5–3 × 1.7–3.5 cm, acute, sometimes broadly mucronate, distal margin usually convex to subsigmoid, usually entire, basal lobules ± patent or subrecurved, proximal margin concave to straight, entire or seldom with a single, short, broad basal tooth; lateral segments in (2) 3 (4) pairs, narrowly triangular, ± arcuate-recurved, ± birdwing-like in older leaves, acute to acuminate, usually 1–2 cm long, 0.5–1.3 cm wide at base, distal margin convex or sigmoid, entire, seldom with a single tooth, proximal margin concave or ± straight, entire or with a single basal tooth; interlobes relatively broad, usually 0.6–1.5 × 0.5–1.7 cm, green, unbordered, usually with a single large tooth or lobule to 7 mm long, otherwise entire or sparsely denticulate; mid-vein pale. Scapes pale greenish at anthesis, very sparsely arachnoid or glabrous, ± equalling leaves. Capitulum relatively small, ca. 3 cm wide, ± flat, yellow. Involucre slightly pruinose, broadly obconical and ca. 8–9 mm wide at base. Outer phyllaries 12–15, loosely appressed and distally erect, later to arcuate-patent, short, reaching 1/3–2/5 of the inner ones, ovate to lanceolate, usually 4–5.5 × 2–3 mm, abaxial surface dark grey-green (almost black when dry), with a slightly darker middle line and an abrupt transition in an inconspicuous, „dirty“ membranous paler border ca. 0.05 mm wide, margin irregularly minutely ciliate, apex flat; inner phyllaries 10–11 mm long, of ± equal width. Outer ligules flat, ± broad, striped purplish grey-brown outside, apical teeth adaxially yellow, abaxially dark grey, inner ligules canaliculate, their apical teeth yellow. Stigmas medium discoloured, brownish yellow with black pubescence outside. Pollen abundant, pollen grains irregular in size. Achenes light stramineous-brown, 3.7–5.0 × 1.0– 1.1 mm, body subdensely shortly spinulose and squamulose in the upper 1/3– 1/4, ± gradually narrowing into a subcylindrical to cylindrical cone (0.6–) 0.8–1.4 × 0.30–0.35 mm, sometimes with a few minute spinules proximally; beak 4.5–6 mm long, pappus white to dirty white, 4–5 mm long. – Agamosperm. – Fig. 57 , 60B .

Diagnostic notes:— Taraxacum fragile is characterized by quite unusual achenes with a long, ± thin cylindrical cone, and yellowish green, ± glabrous leaves. It is similar to T. pseudoalpestre Štěpánek & Kirschner , a species of southern Carpathians.The latter has achenes with a short, conical cone, and more numerous outer phyllaries. Taraxacum fragile is obviously allied to T. musteum , a species easily discernible by more numerous and much narrower outer phyllaries.

Distribution and habitat:—Known from a single macrolocality at the foot of the Mt. Vichren Massif at about 1900 m a.s.l. It grows on gravelly alluvial deposits along Demjanica River. Its IUCN conservation status is estimated as VU.

Figures

FIGURE 57. Taraxacum fragile (PRA, no. det. 36074, holotype). Photo M. Hladík.

FIGURE 60. Achenes of the Bulgarian members of Taraxacum sect. Rhodocarpa. A, T. musteum (PRA, no. det. 35757, holotype); B, T. fragile (PRA, no. det. 36076, isotype); C, T. hamosius (PRA, no. det. 23898); D, T. serenum (PRA, no. det. 26113, isotype). Scale bars = 1 mm.