Taraxacum taimyrense Tzvelev

Kirschner, Jan, Štěpánek, Jan & Buryy, Vladimir V., 2025, Towards a revision of Taraxacum sect. Borealia (Compositae, Crepidinae) in Siberia and the continental Far East, with special reference to the dandelions of the Altai and Kamchatka, Phytotaxa 679 (1), pp. 1-147 : 69-70

25. Taraxacum taimyrense Tzvelev in Tzvelev & Yurtzev (1984: 189) Type:—[ RUSSIA, Krasnoyarsk Region, Taimyr Peninsula, Northern shore of Lake Taimyr , southern promontories of Byrranga Mountains ,

vicinity of Lake Engelhardt, rock outcrops] Severnoe poberezh’e Taimyrskogo ozera, juzhnye predgor’ya khr. Byrranga, okr. oz.

Engel’gardt, po pravom beregu, skal’nye vykhody, 12 Aug 1967, N. Matveeva ( LE, no. det 6032, holotype). Etymology:—Taimyr Peninsula, the nortwestern Siberia .

Plants relatively small but of robust appearance, to 12 cm tall. Petiole usually narrowly winged, green or suffused purplish, tunic absent. Leaves deep green, glabrous, oblanceolate in outline, usually 5–12 × 2.0– 2.5 cm, sometimes undivided and irregularly lobulate or sinuate-dentate, lobules patent, acute, but most often pinnatilobed, with 3–5 irregular pairs of ± patent or variable, narrowly triangular, ± entire lateral segments; terminal segment narrowly triangular or triangular-hastate; interlobes most often broad, sometimes narrow and with a few teeth. Scapes brownish green, often suffused purplish, distally ± arachnoid, subequalling leaves. Capitulum yellow. Involucre dark, blackish green, rounded at base. Outer phyllaries not numerous, ± appressed to loosely so, not imbricate, ± lanceolate, surface dark olivaceous green or black-green, border narrow, paler whitish-green, apex with horns; inner phyllaries ca. 14 mm long, corniculate. Stigmas discoloured. Pollen present (according to the protologue; the type is without florets). Achenes grey-olivaceous to ± dark grey, ca. 5.6–5.7 × ca. 1.2 mm, body ± densely spinulose in upper 1/4, mainly on ridges, ± gradually narrowing into a subcylindrical to subconical cone 1.2–1.3 mm long, 0.4–0.6 mm thick at base, ca. 0.35–0.45 mm distally; beak thin, at least 7 mm long, pappus ± white, conspicuously long, ca. 7.0– 7.5 mm. – Fig. 43 .

Diagnostic notes:— Taraxacum taimyrense has dark, deep grey-olivaceous, tightly appressed outer phyllaries and leaves shallowly to deeply lobed with patent lateral segments. Its most conspicuous feature is the dark grey-olivaceous colour of achenes; they are unusually long, with the achene body gradually narrowing in a subconical to subcylindrical cone 1.2–1.3 mm long.

Distribution:— Taraxacum taimyrense is known from the southern part of the Byrranga Mts., Taimyr Peninsula.

Figures

FIGURE 43. Taraxacum taimyrense. General habit and a detail of achene (both LE, no. det. 6032, holotype).