Taraxacum rhodocarpum Dahlstedt 1907
Creators: name: Štěpánek, Jan
name: Kirschner, Jan
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Asterales
Asteraceae
Taraxacum
Taraxacum rhodocarpum

description: Taraxacum rhodocarpum Dahlstedt (1907: 21)
Type indication:— Hab. in Helvetia ad Zermatt (Canton Wallis) in Gornergrat loco lapidoso humidiusculo in reg. alp. inf., ubi anno 1893 plantam fructiferam inveni.—Vallesia, Monte Bellalp (D. Lagger s. n. T. glaucescens, Herb. Mus. Stockholm)
Type:—[SWITZERLAND, Wallis] Stockh.: Bergianska trädgården, odl. av fr. från Schw.: Zermatt [collected by H. Dahlstedt near Zermatt in 1893, cultivated from achenes in Bergian Botanical Garden, Stockholm], 9 Jun 1904, H. Dahlstedt (S, no. det. 23198, lectotype, designated here)
Residual syntypes:— Ibidem, Jun 1899 & 9 Jun 1904, H. Dahlstedt (S, no. det. 23199); 20 Jun 1900, H. Dahlstedt (S, no. det. 23200, 23201); 29 May 1902, (S, no. det. 23202).
Exsiccate:—Taraxaca Exs., no. 756, as T. schroeterianum.
Illustrations:— Dahlstedt (1907, Plate II, fig. 40–43); herbarium images on JSTOR Global Plants pages (https://plants.jstor.org/).
Description:—Plants usually medium-sized, often subrobust, most often up to 17 cm tall. Leaves deep to dark midgreen, glabrous, rarely (in inner leaves proximally) with a few hairs on mid-vein‘s adaxial surface, usually 8–15 × 3.5–5 cm, young leaves often undivided or with 2–3 subrecurved lateral lobes and ± entire margins, middle leaves usually with 3–5 pairs of acute, narrowly triangular to ± triangular, subrecurved to subpatent lateral segments, distal margin most often sigmoid, usually with a single sub-basal tooth, or with a few little teeth, proximal margin concave, usually entire, often raised; terminal segment triangular or elongated-triangular, entire or with a single shallow incision, basal lobules narrow, acute; petiole glabrous, dark purple, narrow, unwinged; interlobes narrow, or up to 7 mm wide, entire or with 1–2 thin teeth, margin often raised; mid-vein usually purplish. Scapes glabrous, usually purplish, ± equalling or slightly overtopping leaves. Capitulum deep yellow, (2.5–) 3–3.5 cm wide. Involucre dark (blackish) olivaceous-green, rounded and 8–9 mm wide at base. Outer phyllaries (12) 13–15 (16), appressed, subimbricate or not so, lanceolate, narrowly lanceolate, sometimes ovate-lanceolate, usually 6–8 (–9) × 2–2.5 mm, surface blackgreen, border sometimes not visible, sometimes paler, up to 0.5 mm wide, margin ciliate, apex flat; inner phyllaries usually 12–13 mmlong, flat. Outer ligules flat to subcanaliculate, striped deep grey-green outside, often with purplish hue, ligule teeth blackish green. Pollen sometimes absent, usually present, pollen grains irregular in size. Stigmas discoloured, light greyish-greenish. Achenes castaneous-brown or medium dark mid-brown, 4.2–4.8 × 1.1–1.4 mm, body ± densely or subdensely covered with ± robust straight spinules and squamules up to 0.35 mm long in upper 1/4–1/3, subabruptly to subgradually narrowing in a relatively robust subcylindrical cone ca. 0.6–0.9 × ca. 0.4–0.5 mm, beak thin, 6–7 mm long, pappus ± yellowish white, ca. 5.5 mm long.—Agamosperm. 2n=32 (A. Krahulcová 1993: 292; Gustafsson 1932: 48, both under the name of T. schroeterianum).
Taraxacum rhodocarpum, known to occur in the Western Alps of France and Switzerland, is markedly close morphologically to the group of taxa around T. reophilum van Soest (1959: 132). They are very similar in outer phyllary characters and the robust achenes with a thick subcylindrical cone. Taraxacum reophilum, however, is the type of T. sect. Alpestria, and these two species therefore belong to the same section. The inevitable conclusion is that the name T. sect. Alpestria is a younger synonym of T. sect. Rhodocarpa.
description: Published as part of 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, pp. 295-300 in Phytotaxa 548 (2) on pages 297-298, DOI: 10.11646/phytotaxa.548.2.12, http://zenodo.org/record/6597648