Taraxacum orientali-atratum Kirschner & Štěpánek, 2017

Kirschner, Jan & Štěpánek, Jan, 2017, A revision of Taraxacum sect. Atrata, a dandelion group centred in the Middle Asia, and the problem of Taraxacum brevirostre, Phytotaxa 305 (4), pp. 225-261 : 237

4. Taraxacum orientali-atratum Kirschner & Štěpánek , sp. nova

Type: — INDIA. Jammu & Kashmir State, Ladakh, Suru Region, Tongul, valley S of the village, 3800–3900 m, 34º2.42´N, 75º56.83´E, 27 Aug 2005, L. Klimeš 6095 ( PRA, no. det. 28210, holotype).

Diagnosis: — Species nostra T. goloskokovii valde similis, sed foliis integerrimis, phyllariis exterioribus arcte adpressis, multo paucioribus, marginibus distinctis, necnon acheniis pure dilute griseo-brunneis notabilis.

Description: —Plants 10–16 cm tall. Petiole pale green to pinkish, long, narrow, unwinged; leaves (4–) 8–10 × 0.4–0.7 cm, deep green, linear to narrowly linear-oblanceolate, usually entire, sometimes with 1–2 pairs of indistinct minute teeth, glabrous. Scapes brownish-purplish green, totally glabrous, overtopping leaves. Capitulum to ca. 1.5 cm wide. Involucre 5–7 mm wide, base not conspicuously rounded. Outer phyllaries 5–7, blackish, not imbricate, linear-lanceolate to narrowly lanceolate, appressed, unequal, usually 5.0–7.5 × 1.4–2.2 mm, with a sharply delimited variably broad whitish border 0.2–0.4 mm wide, margin glabrous, entire, rarely with 1–2 minute teeth, apex subobtuse, often reddish, flat or with a minute blackish callosity; inner phyllaries 11–12 mm, later to 14 mm long, blackish, apex flat. Ligules yellow, outer ligules ± flat, striped blackish (with reddish borders) outside, ligule teeth distinct, inner ligule teeth ± reddish. Stigmas dirty yellow to slightly greenish yellow. Anthers polliniferous; pollen grains conspicuously irregular in size. Achenes ( Fig. 11H ) pure light grey-brown, 4.9–5.1 × 0.9–1.0 mm, body with a few sparse minute spinules above, cone not developed, achene part above sparse spinules 0.3–0.5 mm long, inconspicuously gradually narrowing into slightly thickened beak 2.8–3.2 mm long. Pappus white, 6–6.5 mm long.—Agamospermous.— Fig. 8B , 11H .

Taxonomic and distribution notes: — Taraxacum goloskokovii , the most similar relative of our species, differs from it in leaves not entire, usually divided into 2–3 pairs of acute subrecurved lobules, outer phyllaries loosely appressed and much more numerous, with a subgradual transition between the dark middle part and paler borders. Taraxacum orientali-atratum is the south-easternmost representative of T. sect. Atrata, and one of the two species known from the Himalaya. Unlike most of the other species treated in the present paper, the name T. orientali-atratum is based on a single herbarium specimen. There are three reasons for describing this new taxon on the basis of a rather scanty material. First, the specimen available is very well preserved and prepared, with both flowers and achenes, and secondly, the occurrence of T. sect. Atrata in Ladakh is extremely remarkable both from the viewpoint of phytogeography ( Fig. 16 ) and the Taraxacum taxonomy. And last, the material available is so distinctive morphologically that it is well possible to draw lines between it and the other species of T. sect. Atrata.

Figures

FIGURE 8. A, T. pseudolilacinum (PRA, no. det. 28224). B, T. orientali-atratum (PRA, no. det. 28210). Scale bar equals 3 cm.

FIGURE 11.Achenes of the members of T. sect. Atrata: G, T. sublilacinum (PRA, #111/2); H, T. orientali-atratum (PRA, no. det. 28210); I, T. pamiricum (PRA, no. det. 28213); J, T. pseudoatratum (LE, no.det. 7973); K, T. pseudolilacinum (PRA, #17); L, T. subglaciale (LE, no. det. 7955). Scale bar = 1 mm.

FIGURE 16. Distribution ranges of T. guntense (circle), T. orientali-atratum (square), and T. pamiricum (triangle).