Taraxacum schroeterianum Handel-Mazzetti (1905: 461)

Štěpánek, Jan & Kirschner, Jan, 2022, Taraxacum rhodocarpum and T. schroeterianum (Asteraceae, Crepidinae) are not synonyms, and T. sect. Rhodocarpa is the correct name for T. sect. Alpestria, Phytotaxa 548 (2), pp. 295-300 : 295-297

Taraxacum schroeterianum Handel-Mazzetti (1905: 461)

≡ Taraxacum laevigatum subsp. schroeterianum (Hand.-Mazz.) Hegi (1928: 1094)

≡ Taraxacum officinale subsp. schroeterianum (Hand.-Mazz.) Schinz & Thellung in Schinz & Keller (1909: 588)

≡ Taraxacum officinale var. schroeterianum (Hand.-Mazz.) Fiori (1928: 812)

Type:—[ FRANCE, Lacs de Tenibres] Voyage botanique dans les Alpes maritimes de Emile Burnat, John Briquet, A. Saint-Yves, François Cavillier et Emile Abrezol (8 juillet – 8 août): Lacs inf. du Tinibras, pré tourbeux, terrain géol. cristallin, 2300 m, 27 Jul 1905, E. Burnat, J. Briquet, A. Saint-Yves, F. Cavillier & E. Abrezol (G-BU, no. det. 22625, lectotype, designated here). Determined by H. Handel-Mazzetti (1905) as Taraxacum Schroeterianum mh .

Note:—After the publication of T. schroeterianum, A. Saint-Yves returned to the Tinibras locality and, on July 27, 1907, collected a rich gathering of T. schroeterianum . The gathering was provided to the Society for the Study of the French-Swiss Flora, and distributed as an exsiccate, Soc. Et. Fl. Fr.-Helv., no. 1791; the specimens represent topotypes. The residual syntypes examined by us are listed in the Appendix.

Illustrations:—Handel-Mazzetti (1907: Plate III, fig. 7a, b; Plate VI, fig. 6).— Uhlemann (2015, fig. 13A–C, fig. 16).

Exsiccates:—Dörfler, Herbarium Normale, no. 4675.—Société pour ľÉtude de la Flore Franco-helvétique 1907, no. 1791.

= Taraxacum sagii Sonck (1990: 39) , syn. nov.

Type:—[ FRANCE] Hautes Alpes , Orcières , Merlette, Forêt des Baniols (alt. 2300 m), pré humide au bord d′un ruisseau, avec Primula farinosa, Juncus triglumis et Carex ferruginea , 24 Jul 1987, C. E. Sonck (H, holotype; isotype: PRA, no. det. 12513)

Description:—Plants usually slender, usually 8–13 cm tall. Leaves glaucous green or ± greyish green, glabrous, most often 4–8 (–13) × 0.7–1.5 (–2) cm, often entire, or with shallow incisions, or with 1–3 pairs of irregular, triangulardeltoid, recurved or subpatent, acute, usually entire lateral segments; in cultivated plants lateral segments in 3–5 pairs, narrowly triangular, subrecurved, acute, with distal margin convex, often with a few teeth, proximal margin ± straight and entire; terminal segment often elongated and entire in wild plants, broadly triangular in cultivated ones; interlobes variously broad, usually entire (often narrow, entire or with a few teeth in cultivated plants); mid-vein usually suffused brownish-purplish; petiole dark purple, thin, unwinged. Scapes glabrous, purplish at base and distally, otherwise brown-green, equalling or ± overtopping leaves. Capitulum golden yellow, ca. 2.5–3 cm wide. Involucre dark olivaceous-green, narrowly rounded to subobconical and 5–8 mm wide at base. Outer phyllaries usually 10–13, appressed, subimbricate, broadly lanceolate to ovate-lanceolate, usually (3.5–) 4.5–5.5 (–6.0) × 1.7–2.2 mm, surface usually blackish olivaceous-green, with a paler border ca. 0.3 mm wide in proximal part, distally suffused purplish, at least marginally, with a narrow membranous border ca. 0.1 mm wide, margin ciliate, apex flat; inner phyllaries ca. 11 mm long, flat. Outer ligules canaliculate to flat, usually striped light purplish grey, inner ligule teeth usually reddish. Stigmas light greyish yellow (i.e., very pale discoloured). Pollen present, pollen grains irregular in size. Achenes purplish brown, 3.5–4.1 × ca. 0.65–0.85 mm, body with a short zone of sparse or subsparse spinulosity (spinules usually 0.1–0.2 mm long, sometimes ascending to lower 1/3 of the cone), gradually narrowing into a subcylindrical to cylindrical cone 0.6–0.9 mm long, 0.25–0.35 mm thick at base, 0.20–0.25 mm distally, beak thin, 5–6 mm long, pappus ± white, 4–5 mm long.—Agamosperm. 2n=24 (H. Dvořáková, unpubl., 12/1999 (PRA, no. det. 37076); Hou-Liu (1963: 79).

Taraxacum schroeterianum is a quite isolated species, perhaps close to the assemblage of T. sect. Alpestria, and with features pointing to possible relationships with T. sect. Palustria ( Lindberg 1908: 17) Dahlstedt (1921: 37) . We refrain from according it a separate sectional status; as shown below, the name T. sect. Rhodocarpa is not applicable to it. It is relatively common in southern Switzerland and in the French Alps (Alpi Graie in Savoie, Alpes Maritimes) and the adjacent Italy; marginally, it reaches Austria (Tirol) and the southernmost Germany (the Allgäuer Alpen).

Note:—The name Taraxacum sagii Sonck was originally placed in T. sect. Palustria ; Kirschner & Štěpánek (1998: 270) listed T. sagii among species unclear due to the insufficient material. We revisited the name T. sagii now, reassessed its complete original material, and concluded that it belongs to T. schroeterianum .