Taraxacum sandomiriense Wolanin, 2018

Wolanin, Mateusz Marian, Musiał, Krystyna & Wolanin, Magdalena Natalia, 2018, Taraxacum sandomiriense (sect. Erythrosperma, Asteraceae), a new species from Poland, Phytotaxa 375 (2), pp. 158-164 : 159-162

Taraxacum sandomiriense Wolanin , sp. nov. ( Fig. 1, 2 , 3 )

Description: —Plants small to middle-sized with rich leaf-rosettes, older specimens with a tunic. Leaves greyish-green, dull, hairy on an upper side (40–60 hairs per 5mm 2), usually 3–5 × longer than wide, approximately (3–)5–10(– 15) cm long and 1–2.5 cm wide. Leaf blade narrowly oblanceolate, usually broadest in upper 1/3, having 6(–7) pairs of lateral lobes. Lateral lobes opposite to remote, of the inner leaves narrowly triangular, patent, with a distal margin entire of slightly dentate, somewhat convex; proximal margin usually entire or with a few small teeth at margin. Lateral lobes of the outer leaves triangular, entire or with a few teeth at distal margin. Interlobes often toothed. Terminal lobes of the inner leaves tripartite, mostly lingulate and entire on the margins. Terminal lobes of the outer leaves triangular. Petioles unwinged, pale purple, hairy. Scapes as long as or longer than leaves, hairy, especially just under the capitulum. Capitulum convex, 2.5–3.0 cm in diameter, yellow, outer strips grey-violet. Inner bracts greyish-green, corniculate. Outer bracts usually 10–14, lanceolate, usually 5–7 mm long, 2–2.5 mm broad, purplish green, with a distinct white hyaline margin (0.1–0.2 mm broad), recurved and strongly corniculated. Stigmas yellow-greyish, pollen (irregularly sized) present. Achenes brown, in the upper part with thin spinules, 3.4–4.0 mm long (incl. the 0.8–1.2 mm long, narrowly conical pyramid) and (0.7–)0.8(–0.9) mm broad, a rostrum 8.5–10 mm long, and the pappus white. Flowering IV (V).

Type: — POLAND. Kamień Łukawski , path on the edge of the loess slope (near the reserve), 50º 41’N, 21º 47’E, 6 May 2013, M. Wolanin (holotype KRA 476861 ; isotype KRA 476862 ) .

Distribution and habitat: —So far, Taraxacum sandomiriense has been known only from three localities in the eastern part of the Świętokrzyskie Province. The distance between the furthermost localities of this species is 30 km ( Fig. 4). All populations of T. sandomiriense were found on erosive rocky slopes of river valleys with south-western exposure, in xerothermic phytocoenosis (Festucion vallesiacae Klika 1931) overgrown with shrubs. The species was most often accompanied by Centaurea scabiosa L., Euphorbia cyparissias L., Koeleria macrantha (Ledeb.) Schult. , Medicago falcata L., Alyssum alyssoides (L.) L., Achillea pannonica Scheele , Festuca rupicola Heuff. , Festuca trachyphylla (Hack.) Hack. , Campanula sibirica L., Stachys recta L., Arenaria serpyllifolia L., Salvia pratensis L., Ulmus minor Mill. , Juniperus communis L. and Pyrus pyraster (L.) Burgsd.

Etymology: —The species name refers to the town of Sandomierz (latinized as Sandomiria), the place where specimens of this taxon were collected for the first time.

Karyology: —Karyological analysis showed triploid chromosome number of the examined root tip meristems, 2n=3x=24 (Fig. 5).

Species conservation assessment: —Although Taraxacum sandomiriense has been present in the Świętokrzyskie region for almost 100 years, as shown by the results of this study, it should be considered an extremely endangered species, among others, due to its very limited range and populations with a small number of individuals. However, the biggest threat to this species is the overgrowing of xerothermic grasslands by shrubs and trees (especially at the stands in Podgrodzie and Gałkowice-Ocin), which leads to an increase in shade and overgrowth of T. sandomiriense habitats by higher perennials. Positive factors for the survival of this species include rock erosion in Podgrodzie and trampling paths on the sunny loess slopes in Kamień Łukawski that give rise to small, unbounded spaces on which the plants of this taxon can spread and vegetate. Using IUCN categories ( IUCN 2001), the species should be considered as Critically Endangered due to its small distribution range (EOO = 9.68 km 2) and very small populations (<20).

Additional specimens examined: — POLAND. Gałkowice-Ocin , xerothermic grassland on the south-western slope, 50º 44’N, 21º 43’ E, 17 April 2012, M. Wolanin & M. Nykiel ( UR! MW003442 ) ; Podgrodzie near Ćmielów, xerothermic grassland on the rock cliff, 50º 54’ N, 21º 32’ E, 17 April 2012, M. Wolanin & M. Nykiel ( UR! MW003431 ) ; Podgrodzie , xerothermic grassland on the rock cliff, 50º 54’ N, 21º 32’ E, 13 April 2017, M. Wolanin & M. N. Wolanin ( UR! MW003421 ), ( UR! MW003422 ) ; Sandomierz , Strzelecka Hill, loess slope, 10 May 1924, A. Kozłowska ( KRA! 76947) .

FUGURE 5. Mitotic chromosomes of Taraxacum sandomiriense , 2n = 3x = 24. Scale bar = 5 μm.

Similar species: — Taraxacum sandomiriense is characterized by a unique combination of specific features (hairy upper side of the leaves, strongly corniculated outer bracts, presence of abundant pollen, brown fruit color), which clearly distinguishes this taxon from all other European dandelion species of the Erythrosperma section. However, due to some traits, it may somewhat resemble T. danubium Richards (1970b: 108) , T. frondatum Øllgaard (2015: 5) , T. dentosum Christiansen (1936: 8) , T. falcatum Brenner (1907: 354) , T. proximum ( Dahlstedt 1905: 152, 165) Raunkiaer (1906: 258) and T. persicum Soest (1960: 312) ; the main diagnostic features distinguishing these dandelion taxa are summarized in Table 1.

Figures

FIGURE 2. Taraxacum sandomiriense. Plants collected from the locality in Podgrodzie. Scale bar = 5 cm.

FIGURE 3. Taraxacum sandomiriense. A: blooming plant; B: achenes; C, D: outer bracts arrangement.