Taraxacum minuticarpum 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

17. Taraxacum minuticarpum Kirschner & Štěpánek , sp. nov.

Type:—[ RUSSIA, Respublika Altay] Siberia austro-occidentalis, montes Altaj, distr. Koš-Agač, in valle fl. Čuja , pagus Čagan-Uzun , in arenosis et glareosis ad ostium fl. Kujach-Tonar , ca. 1900 m, 5 Jul 1988, J. Kirschner, cultivated as JK 24 ( PRA, no. det. 33407, holotype; isotype: PRA, no. det. 33401) .

Etymology:—With very small fruits.

Diagnosis:—Plantae tunicatae polline carentes vel rarius sparsissime polliniferae, notabiles petiolis sordide purpureis, phyllariis involucralibus exterioribus adpressis vel laxius adpressis, ovato-lanceolatis usque ovatis obscure olivaceo-viridibus, marginibus fere invisibilibus, ad 0.1 mm latis, ciliatis, ligulis externis plerumque cucullatis, acheniis rubro-brunneis angustis, corpore persensim in pyramidem subcylindricam vel subconicam transeunte.

Plants very small, usually to 6 cm tall. Petiole narrow, unwinged, suffused grey-purple, ± arachnoid; plant base with whitish hairs, tunic developed. Leaves deep green, subglabrous to very sparsely arachnoid, oblanceolate in outline, usually 3.5–5.5 × 1–1.5 cm, pinnatisect, shape variable, ± complicated, some (usually outer) leaves with 3–4 pairs of subrecurved, narrowly triangular lateral segments with distal margin subentire or with a single tooth, interlobes short with 1–2 short but distinct teeth; the inner leaves with 3–4 patent to subrecurved, narrowly triangular to lineartriangular lateral segments, distal margin with a short lobule or an incision near the segment’s base, proximal margin entire, interlobes longer, with 1–3 distinct patent lobules or large teeth; terminal segment broadly triangular or ± helmet-shaped, most often entire, basal lobules usually patent; mid-vein ± purplish. Scape brownish green, arachnoid, equalling or overtopping leaves. Capitulum lighter yellow, not fully opening, usually ca. 2 cm wide. Involucre dark green, ca. 5–7 mm wide and ± rounded at base. Outer phyllaries 10–13, ± not imbricate to subimbricate, appressed to loosely appressed, ovate-lanceolate to ovate, (3.5–) 4.2–5 × (1.8–) 2.0– 2.2 mm, dark olivaceous-green, distally darker and usually suffused reddish, border ± not visible, ± membranous, to 0.1 mm wide, margin ciliate, apex flat. Outer ligules involute, cucullate, striped blackish purple outside, inner ligule teeth dirty yellow or slightly purplish. Stigmas greyish to grey-yellow. Pollen absent, but sometimes some irregular pollen grains hidden in anther tube. Achenes medium red-brown to slightly reddish medium brown, 2.9–3.2 × 0.7–0.8 mm, body with numerous but not dense, thin, erect-patent spinules in upper 1/3, body ± gradually narrowing into subcylindrical to subconical cone 0.6–0.7 mm long; beak 6 mm long, pappus ± white, 4–4.5 mm long. – Agamosperm. – Fig. 19 .

Diagnostic notes:—The ± borderless, not numerous, ovate-lanceolate to ovate, short outer phyllaries, the halfclosed capitulum with cucullate ligules, empty or sparsely polliniferous anthers, the small size of red-brown achenes are diagnostic. The differences between T. minuticarpum and T. depauperatum are summarized in the treatment of the latter.

Distribution and habitat:—The flat, relatively dry, sandy to gravelly alluvial sediments in the vicinity of the conflunce of the rivers of Chuya and Kuyakh-Tonar, Kosh-Agach District, Altai Republic, are rich in dandelions of T. sect. Suavia and T. sect. Dissecta . Taraxacum minuticarpum is not very conspicuous among them; it is known to occur at that macrolocality only.

Specimens examined:—[ RUSSIA, Respublika Altay] Altai Republic, Altai Mts., Kosh-Agach District, valley of the river Chuya, village of Chagan-Uzun , sandy and gravelly sites near the mouth of river Kuyakh-Tonar , ca. 1900 m, 5 Jul 1988, J. Kirschner, cultivated as JK 24 ( PRA, no. det. 33401, with duplicates) .

Figures

FIGURE 19. Taraxacum minuticarpum. A, General habit; B, Achenes (both from PRA, no. det. 33407, holotype). Achenes are more reddish when viewed in daylight.