Taraxacum ceratophorum (Ledeb.) Candolle (1838: 146)

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 : 89-91

35. Taraxacum ceratophorum (Ledeb.) Candolle (1838: 146) ≡ Leontodon ceratophorus Ledebour (1829: 9) Type:—[ RUSSIA, Kamchatka] “Sem. in Kamtschatka legit Eschscholtz” [Seeds collected by Eschscholtz in Kamchatka, determined as:]

“ Leontodon kamtschaticus m. ” [which is crossed out and replaced by] “ Leontodon ceratophorus m. ”, [Eschscholtz] (LE, no. det.

6134, lectotype, fide Tzvelev 1992: 376, see also Kirschner et al. (2014: 587).

= Taraxacum trigonolobum Dahlstedt (1926b: 8)

Type:—[ RUSSIA, Kamchatka, selected syntypes studied] Bassein Kronockago ozera, gora Krascheninnikova , 19 Aug 1909, V. Komarov 3248 ( LE, no. det. 6031, syntype) . – Kamtchatka, Avatschavulkanen , 675 m, 30 Jul 1920, E. Hultén 610 ( S 13-11608 !, syntype) .

= Taraxacum aleuticum Tatewaki & Kitamura in Tatewaki & Kobayashi (1934: 89)

Type:—[ USA, Alaska, Aleutian Islands] Atka , 6 Jul 1929, M. Tatewaki & K. Takahashi [ SAP, holotype, n. v., fide Haglund, Svensk Botanisk Tidskrift 40: 341 (1946)] .

= Taraxacum atkaense Tatewaki & Kitamura in Tatewaki & Kobayashi (1934: 90)

Type:—[ USA, Alaska, Aleutian Islands] Atka , 27 Jun 1931, Y. Kobayashi [ SAP, holotype, n. v., fide Haglund, Svensk Botanisk Tidskrift 42: 330 (1948)] .

Note:—For the explanation of the above synonymy, see p. 11–13.

Plants medium-sized, usually 12–17 cm tall. Petiole pale green, glabrous, broadly winged, plant base without tunic. Leaves light green, ± glabrous, ± oblanceolate in outline, usually 5–11 × 1.7–2.8 cm, sometimes undivided, usually pinnatifid to pinnatipartite; terminal segment flat triangular or flat rhombic, often subobtuse, or with a minute mucro, margins ± entire; lateral segments in 3–4 pairs, patent to subpatent, usually deltoid to deltoid-triangular, distal margin subconvex or straight, entire or with a single short tooth, proximal margin usually straight, entire; interlobes short and broad, ± entire; mid-vein pale greenish. Scapes brownish green, often suffused light reddish, distally densely arachnoid or ± arachnoid, ± overtopping leaves. Capitulum light yellow to yellow, ca. 3–4 cm wide. Involucre deep olivaceous green, slightly pruinose, 8–11 mm wide and rounded to broadly rounded at base. Outer phyllaries usually (11–) 13–16 (–20), appressed, imbricate, outer of them ± broadly ovate to ovate, usually 4.0–5.5 × 3.2–3.8 mm, inner of them usually 5.8–6.2 (–7.5) × 2.0– 2.5 mm, surface blackish olivaceous-green, with a black line in the middle and a variously broad blackish olivaceous-green zone, with a gradual transition into a lighter olivaceous-green zone (usually to 0.8–1.0 mm wide) and ± sharply delimited whitish or whitish-membranous border usually 0.3–0.4 mm, sometimes to 0.7–0.8 mm wide; sometimes phyllaries wholly black-green, then the paler zone is lacking, and the border is quite distinct, margin ± ciliate, apex with dark horns 1–2 mm long (in later capitula); inner phyllaries 11–14 mm long, olivaceous-green, often coalescing, apex corniculate. Outer ligules flat, very faintly striped light greyish or unstriped outside, teeth dirty yellow. Stigmas discoloured, yellowish green. Pollen present, pollen grains irregular in size. Achenes light greyish stramineous-brown, ca. 4.3–4.4 × ca. 1.0 mm, body ± densely spinulose in upper 1/3, subabruptly narrowing in a subconical cone ca. 0.7 mm long, ca. 0.5 mm thick at base, ca. 0.35 mm distally; beak ca. 10 mm long or longer, pappus white to yellowish white, 6–6.5 mm long. – Agamospermous. – Fig. 2 , 59 .

Note:— Dahlstedt (1926b: 8) reported the absence of pollen in T. trigonolobum . In the LE syntype cited above, pollen is present, in the other syntype (herb. S) we found only sparse pollen grains. Other specimens seen are polliniferous. The lectotype specimen of T. ceratophorum is polliniferous.

Diagnostic notes:— Haglund (1946, 1948) discussed the characters of T. ceratophorum (as T. trigonolobum ) in considerable detail, mainly when comparing it with T. chamissonis Greene (1901: 230) . The most conspicuous features of T. ceratophorum s. str. are the imbricate, relatively short outer phyllaries with a variably broad but always distinct whitish to whitish-green border, and the leaf shape with broad, patent, ± deltoid lateral segments, see also Fig. 2 under T. ceratophorum , and Haglund (1948, fig. 20).

Distribution:—The distribution range of T. ceratophorum s. str. was summarized by Haglund (1948: fig. 21); in Asiatic Russia, it is confined to the SE. Kamchatka, Commander Islands, and it was documented from southern Alaska, including Kodiak, and from the Aleutians. The two gatherings from Kamchatka, see below, are considered as uncertain representatives of T. ceratophorum s. str.

Specimens examined:—[ RUSSIA, Kamchatskiy Kray] Commander Islands, Mednyy Island, Gladkovskaya Bukhta [bay], 3–10 m from the beach, 23 Jun 1992, A. Rzhavskiy (KAM, no. det. 36854, 36780). – Commander Islands, Mednyy Island, rocks by the sea, 7 Jul 1992, A. Rzhavskiy (KAM, no. det. 36771). – Less certain identification:— Kamchatka, Bystrinskiy District, Bystrinskiy Nature Park, NW. part of the Park, 56°25.510’ N, 157°42.527’ E, turf among stones near a brook, 747 m, 18 Jul 2014, V. V. Buryy (herb. V. V. Buryy, no. det. 36848). – Kamchatka, Bystrinskiy District, Sredinnyy Khrebet, upper Bystraya River, near the Marina Pass , ca. 1000 m, 31 Jul 1988, O. Chernyagina (KAM, no. det. 36856, 36853). – Numerous localities from the Aleutians and the adjacent Alaska were listed by Haglund (1946, 1948).

Figures

FIGURE 2. Taraxacum ceratophorum sensu stricto. A, detail of flower heads with involucre (A, LE, the specimen 2 in the above survey). B, C, a comparison with a similar morphotype of T. ceratophorum s. str. from Alaska (Kukak Bay, 1–5 Jul 1899, F. V. Coville & T. H. Kearney 1890, US 1185949, det. by G. E. Haglund).

FIGURE 59. Taraxacum ceratophorum s. str. A, a late flower head in an early stage of development (KAM, no. det. 36854); B, achene (LE, no. det. 6031).