Taraxacum varians Kirschner & Štěpánek, 2023

Kirschner, Jan & Štěpánek, Jan, 2023, A taxonomic revision of Taraxacum sect. Dissecta, a continental steppe group common in Siberia and adjacent regions of Central Asia, Phytotaxa 590 (1), pp. 1921-1935 : 1921-1935

26. Taraxacum varians Kirschner & Štěpánek , sp. nov.

Type:—[ RUSSIA, Respublika Altay] Sibiria austro-occid., montes Altaj, distr. Koš-Agač, in valle fl. Čuja , ad ostium fl. Tjurguň [SW. Siberia, the Altai Mts., Kosh-Agach District, valley of Chuya River, near the confluence with Tyurgun’ River], 5 Jul 1988, J. Kirschner, cultivated from achenes of JŠ 3403 as T 209 ( PRA, no. det. 35974, holotype; isotypes: PRA, no. det. 36631) .

Etymology:—Varying, variegate, fluctuasting.

Exsiccates:— Taraxaca Exs., no. 1354–1355.

Diagnosis:—Species distincta foliis pinnatisectis, lobis lateralibus numerosis, utroque latere numero 5–8, phyllariis involucralibus exterioribus erectis vel erecto-patentibus marginibus pallidis latis, necnon acheniis rubro-brunneis, corpore in pyramidem subcylindricam, saepissime 0.8–0.9 mm longam subsensim transeunte.

Plants medium-sized, sometimes small, usually to 15 cm tall. Petiole light brownish pink or only bordered pink, short, unwinged to narrowly winged; plant base with dense light brownish hairs, tunic ± developed. Leaves numerous, slightly greyish mid-green, not spotted, sparsely arachnoid beneath, later ± glabrescent, linear-elliptic in outline, usually 7–12 × 1.5–2.5 cm, pinnatisect, with 5–8 pairs of patent, less often subrecurved, relatively short, usually narrowly triangular, less often deltoid-triangular or linear-triangular lateral segments 0.7–1.2 cm long, distal margin usually straight, sometimes subconcave, usually with one or several little teeth, often also with an acute lobule in the angle between the segment and the distal interlobe, proximal margin ± straight, entire, seldom with a single little tooth, apex acute; terminal segment triangular to subtripartite, relatively short, distal margins straight to subconcave, entire or with a sigle distinct tooth or a basal incision, basal lobules patent, proximal margin entire; interlobes usually short, sometimes narrowly bordered purple, entire or with a few little teeth; mid-vein pale green to pinkish. Scapes brownish green, arachnoid to sparsely so, ± equalling leaves. Capitulum yellow, 2.5–3.5 cm wide. Involucre slightly greyish deep green, usually 8–9 mm wide and broadly rounded at base. Outer phyllaries usually 13–16, ± not imbricate, most often erect to erect-patent, some patent to arcuate-patent, of variable shape, usually lanceolate, but some (the innermost ones) sometimes linear to linear lanceolate, usually 8–9.5 (–10) × (1.2–) 2.5–3.5 mm, abaxially deep green with a greyish hue, with a usually distinct whitish-membranous border (0.2–) 0.3–0.4 (–0.5) mm wide, and an adjacent paler zone up to 1 mm wide, margin initially ciliate, later usually glabrescent, apical part often suffused pinkish, apex flat, callose or corniculate; inner phyllaries usually 13–15 mm long, often corniculate. Outer ligules flat, usually striped deep greenish grey, sometimes purplish grey, inner ligule teeth grey-purple. Stigmas light greenish with grey pubescence outside. Pollen present, pollen grains irregular in size. Achenes red-brown, usually 3.5–3.7 × 0.7–0.8 mm, body subdensely shortly spinulose/squamulose in upper 1/4, subgradually narrowing into a subcylindrical cone 0.8–0.9 (–1.1) mm long, 0.3 mm thick at base, ca. 0.25 mm distally; beak 7.5–8 mm, pappus ± white, 5–5.5 mm long. – Agamosperm. – Fig. 29 .

Diagnostic notes:—Among members of T. sect. Dissecta , T. varians is distinct in its relatively robust growth, numerous leaf lateral segments, outer phyllaries not appressed, of a relatively narrow shape, and distinctly pale bordered. The size, spinulosity and cone length of achenes appear to be relatively variable ( Fig. 29 B ).

Distribution and habitat:—It is known from the Altai Mts., from several sites in the valley of the Chuya River in Ust-Ulagan District and the western part of Koch-Agach District. It grows on gravelly and sandy alluvial sites along rivers and at disturbed, dry sites in the village vicinity, usually between 1700 and 1900 m a.s.l.

Specimens examined:—[ RUSSIA, Respublika Altay] Altai, Ust-Ulagan District, dry sites along the road near the village of Aktash , 2 Jul 1988, J. Kirschner 206, cultivated from achenes of JŠ 3368 as T 206 ( PRA, no. det. 35976). – Ibidem, J. Kirschner, cultivated as JŠ 3368 ( PRA, no. det. 35978) .

Figures

FIGURE 29. Taraxacum varians. A, General habit; B, Achenes (both from PRA, no. det. 35974, holotype), more reddish under daylight.