Taraxacum brevicorne Dahlstedt (1906: 11)

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 : 73-74

27. Taraxacum brevicorne Dahlstedt (1906: 11)

Type:—[ RUSSIA] Sibiria, Jenisei, Tolstoi nos, 28 Aug 1876, M . Brenner ( S 12-28566 !, syntype). – Novaja Semlja , sinus Karmakulski, 29 Aug 1901, O . Ekstam ( S 12-28575 !, syntype). – Expéditions suédoises de 1875 et de 1876 au Yénissei, région méridionale de la Nouvelle-Zemle, Jul 1875, sine coll. ( S 12-28581 !, syntype). – Insula Wajgatsch , Cap Grebenij [Cap Greben’], 30–31 Jul 1875, F. R . Kjellman & A. N . Lundström ( S 12-28579 !, syntype). – Lena, Jakutsk , Kieferwaldung, [24 Jun 1901], A. K . Cajander ( H, n. v.; S 12-28580 !, syntype fragment, unripe achenes) .

Note:—There is another syntype, not seen by us: “Sibirien: Jenisei, Dudino ( M. Brenner 1876, H. Hafn. [= C])”.

Etymology:—With short horns.

Note:— There are another two syntypes cited among elements of the original material, both from herbarium B. They are not extant. The name T. brevicorne has not been typified, and, because of a rather scanty and incomplete material, the original material may be heterogeneous. Although we have seen almost all the syntypes, we refrain from selecting a lectotype; a more representative material is to be studied .

Plants relatively small, of ± robust growth, to 12 (–20) cm tall. Petiole very narrowly winged, unwinged in inner leaves, greenish or suffused purple, glabrous, tunic absent. Leaves ± deep green, glabrous, ± oblanceolate in outline, ca. 4–8 (–13) × 1.5–2.5 (–3.5) cm, ± undivided, with 2–5 pairs of patent to recurved, subacute, short, triangular teeth, rarely ponnatilobed, with 2–4 pairs of flat triangular-deltoid, short lateral lobes, margins entire, apex subacute; mid-vein usually suffused purplish. Scapes brownish green, glabrous or with sparse arachnoid hairs below capitulum, purplish at base, overtopping leaves. Capitulum deep yellow, ca. 3 cm wide. Involucre blackish green, ca 7–8 mm wide and narrowly rounded at base. Outer phyllaries usually 10–12, appressed, sometimes distally loosely appressed, slightly imbricate, lanceolate to narrowly lanceolate, 5.5–7.0 (–8.2) × (1.6–) 1.8–2.2 mm, surface evenly black-green, with a sharply delimited but not conspicuous, whitish border to ca. 0.1 mm wide, margin glabrous or sparsely ciliate, apex with a thick, obtuse, black horn; inner phyllaries blackish green, 11–13 mm long, corniculate, sometimes coalescing. Outer ligules ± canaliculate, striped pale greyish-purplish to dark purplish grey outside. Stigmas discoloured. Pollen present. – Fig. 46 .

Note:— Achenes , although not fully ripened, are present on the Cajander’s gathering from Yakutsk on Lena River. Because of the enormous distance from the other syntype localities, and the position in another river system, we did not use that material for our description. Schischkin (1964: 472, with N. N. Tzvelev) gave a description of achenes as light greyish stramineous-brown, ca. 4 mm long, body spinulose in upper 1/2, cone ca. 0.5 mm long; beak 8–10 mm long, pappus white, 6–7 mm long. The syntype S 12-28581 also includes an envelope with unripe achenes and a drawing of one; they are ca. 3.8 mm long, sparsely spinulose above, with a subgradual transition into a subconical cone ca. 0.8–0.9 mm long .

Diagnostic notes:—The closest species to be compared with T. brevicorne is T. macilentum . Diagnostic features of the former include a broader leaf shape (± oblanceolate), petiole narrower, outer phyllaries usually longer, with an inconspicuous, very narrow but always visible paler border, and probably a shorter cone. There are also European taxa similar to T. brevicorne : Taraxacum simulum Brenner (1907: 109) differs in its very broad petioles and arcuate outer phyllaries, T. tornense Fries (1908: 142) has a different leaf shape, winged petioles and arcuate outer phyllaries, and T. cornutum ( Dahlstedt 1905: 163) Dahlstedt (1906: 13) is similar in the leaf shape but has longer outer phyllaries, longer achenes with a long cone, and golden yellow stigmas.

Distribution:— Taraxacum brevicorne , as characterized in the present treatment, is probably confined to the northwestern Siberia in Asiatic Russia, mainly to the Yenisey mouth region, and is known from Waigach Island and southern Novaya Zemlya. For unknown reasons, it was not included in Flora of Siberia ( Krasnikov 1997) while Tzvelev (1987b) relegated this name to the synonymy of T. ceratophorum ; on the contrary, Schischkin (1964) listed a number of regions with the occurrence of T. brevicorne across most of Asiatic Russia.

Note:—There is a very similar species reportedly confined to Novaya Zemlya, T. novae-zemliae Holmboe (1923: 87) . It differs from T. brevicorne in the absence of pollen, a more distinct border to outer phyllaries, a broader shape of outer phyllaries and probably also in a longer cone. The original material of T. novae-zemliae is also rather scanty, and both names (taxa) require further study.

Figures

FIGURE 46. Taraxacum brevicorne. Details of involucre and outer phyllaries (A, S 12-28575; B, S 12-28581; C, S 12-28579, syntypes). Scale bar for B = 3 mm.