Taraxacum mirabile Wagenitz (1962: 279)

Kirschner, Jan, Gürdal, Bahar, Štěpánek, Jan & Zeisek, Vojtěch, 2021, Taraxacum mirabile, an enigmatic sexual halophilous endemic dandelion, represents a new section, Phytotaxa 489 (1), pp. 49-64 : 53-55

Taraxacum mirabile Wagenitz (1962: 279)

Type:—[ TURKEY] Zentral-Anatolien, Prov. Niğde, Südwestseite des Tuz Gölü, Salzwiese mit Aeluropus litoralis , Plantago crassifolia , Inula seidlitzii , Limonium globuliferum u. a., 6 Oct 1957, G. Wagenitz & H.- J. Beug 321 ( B, no. det. 22202, holotype; isotypes: E, no. det. 11692; WU, no. det. 8946; GOET, photo!).

Illustrations:— Wagenitz (1962: 280); Yıldırımlı & Doğru-Koca (2005: 10, 11, 12).

Plants dwarf, 2–4 (–5) cm tall. Petioles pale greenish to pale yellowish, glabrous, narrowly winged, conspicuously dilated at base, to 4–5 mm wide; plant base with a well developed arachnoid tunic, and with a conspicuous, very dense bright white arachnoid tomentum of hairs usually 4–5 mm long. Leaves conspicuously fleshy, light green to midgreen, glabrous, narrowly linear-oblanceolate to linear-spatulate, usually 2–2.8 (–4.2) × 0.2–0.3 (–0.6) cm, undivided, usually entire, with ± thickened margins, rarely with a few minute remote white cartilaginous teeth to 0.5 mm long, apex subobtuse, usually white cartilaginous, the cartilaginous part usually to 2 mm wide and ca. 0.5 mm long. Scapes brownish green, very densely arachnoid-tomentose throughout, subequalling to slightly overtopping leaves. Capitulum pure white, with few florets [usually (9) 12–16, rarely to 18], ca. 1.5 cm wide. Involucre light green to light yellowish green, pruinose to almost waxy pruinose, often suffused pale fulvous to pale pinkish, narrowly cylindrical, usually (2.0–) 2.5–3.5 mm wide. Outer phyllaries (7) 9–10 (12), appressed to ± loosely appressed, sometimes with a recurved tip or erect, conspicuously imbricate, the outermost ones usually triangular-ovate to ovate-lanceolate, (1.5–) 2.0–3.0 (–3.5) × 1.0– 1.7 mm, the inner ones of them narrowly lanceolate, (2.5–) 3.5–4.2 (–4.8) × 0.7–1.1 mm, surface light green, greyish-green or light fulvous to light pinkish brown, sometimes with a dark thin middle line or a medium broad dark central part with a gradual transition into a paler, usually white or whitish border of variable width, usually from 0.1–0.2 to 0.3–0.4 mm wide, margin long ciliate at apex, surface glabrous or occasionally with a few short appressed arachnoid hairs near phyllary base, apex flat; inner phyllaries few (7–10), usually 7–9 (–10) mm long, usually 1.2–1.5 mm wide, of ± equal width, apex flat to ± callose. Outer ligules flat, white inside, striped pale pinkish outside, ligule teeth pale greyish. Stigmas yellow (sometimes pale greenish yellow when dry). Pollen present, pollen grains regular in size, usually 28–32 μm in diameter. Achenes light greyish or light greyish with a fulvous tinge, 3.1–3.5 × 0.8–0.9 mm, body very sparsely and minutely spinulose in the upper 1/4–1/5, short spinules confined to low ridges, remote, erectpatent to slightly curved upwards, less than 0.1 mm long, body covered with usually erect-patent, dense to subsparse, little hair-like protuberances usually 10–17 μm long, relatively thin, straight or curved or flexuous, the appearance of achene surface under the magnification of 100–170 is pubescent to tomentose, body ± gradually narrowing into a short, thick conical to subconical cone 0.2–0.25 × 0.3 mm, beak distinct, thickened, short, usually 0.9–1.0 (–1.3) × 0.3 mm, pappus white, 4–4.8 mm long. – Diploid (2n=16, Fig. 4 ), sexual ( Fig. 8E ). – Late flowering. – Figures 5 , 6 , 7 , 8A–8D .

Note 1:—The achene length reported in the protologue and repeated by van Soest (1975), i. e., 5 mm or longer, refers to the length of achene including beak.

Other specimens examined:— TURKEY. Aksaray, 7 km E of Eskil towards the southern saline shores of Tuz Gölü Lake , saline scrub vegetation, 919 m, 38°24’58” N, 33°28’30” E, 28 Aug 2004, H . Akhani 17996, E . Doğan , M . Ekici & M . Ghasemkhani (herb. H. Akhani, no. det. 26454) . – Aksaray, Eskil, 1.3 km east from Eskil center [38°24’23” N, 33°26’13” E], south of Tuz Gölü , 910 m, 14 Sep 2019, B . Gürdal BG1010-68 & E . Abamor ( PRA, no. det. 33693; ISTE 116904 !). – B4 Aksaray, Eskil, from Eskil to edges of Tuz Gölü 5 km, halophytic steppe [ca. 38°25’ N, 33°29’ E], 914 m, 24 Sep 2006, Ş . Yıldırımlı 32238 & A . Doğru-Koca (herb. Yıldırımlı , HUB, photo!). – B4 , Tuz Gölü, Aksaray, Eskil (soil pits ...), 950 m, 25 Aug 1997, M . Aydoğdu 3831 ( ANK!). – B4 , Konya, Gölyazı – Tersakan Gölü , 930 m, göl kenarı, tuzlu topraklar [between the village of Gölyazı and Tersakan Lake, lake edge, saline soils, ca. 38°33’ N, 33°09’ E], 25 Sep 1996, M . Vural 7714 ( GAZI!). – B4 , Aksaray, Eskil – Yenikent, Tuz Gölü güney ı, tuzlu topraklar [ NE of Eskil, towards Yenikent, south of the lake, saline soils], 38°24’45” N, 33°27’23” E, 23 Sep 1997, M . Vural 8048, H . Duman & Z . Aytaç ( GAZI!) .

Note 2:— van Soest (1975), in addition to the type gathering, lists another two T. mirabile specimens from a remote NW. Anatolian area of Bolu and the Abant Lake. Both these localities (see below for details), and the Abant Lake in particular, are ecologically totally different from the Tuz Gölü lake conditions. We studied high resolution digital images of these two herbarium specimens (Curators, Herbarium B 2019+), both listed under the name T. serotinum ( Waldstein & Kitaibel 1802: 119) Fischer (1808: 55) by Wagenitz (1962); they indeed belong to T. serotinum . It is probable that a reference to them under the name of T. mirabile was made as a result of data confusion (perhaps due to a rather strange layout and format of individual species‘ paragraphs in Wagenitz 1962). – Taraxacum serotinum :— TURKEY. Prov. Bolu, südlich Bolu, ca. 800–850 m, Stoppelfeld [stubble field], 8 Sep 1957, G. Wagenitz & H.- J. Beug 22 ( B 101094294, photo!). – Prov Bolu, am Abant Gölü, südwestl. Bolu, ca. 1300 m, Trockenrasen, 10 Sep 1957, G. Wagenitz & H.- J. Beug 59 ( B 101094295, photo!).

Distribution and ecology:— Taraxacum mirabile (also with regard to the Note 2 above) is known from the vicinity of southern shores of Tuz Gölü in Central Anatolia, Aksaray and Konya Provinces, Turkey ( Fig. 2 ). It was also documented from an area near the eastern shores of another, smaller saline lake in the same region, Tersakan Gölü. We therefore consider T. mirabile as a stenoendemic species of that area. As regards the ecology, T. mirabile is reported to be accompanied by Plantago crassifolia Forssk. , Aeluropus litoralis Parl. , Inula seidlitzii Boiss. and Limonium globuliferum Kuntze , which places T. mirabile in the vegetation of Atropis distans-Limonium gmelinii association ( Zeydanli 2019), with further species accompanying it, e.g., Juncus maritimus Lam. , Salicornia europaea L., Halocnemum strobilaceum (Pallas) M. Bieb. , Puccinellia distans (Jacq.) Parl. and Verbascum pyroliforme (Boiss. & Heldr.) Kuntze ( Fig. 3 ). As regards the biology of T. mirabile , it is well adapted to the extreme conditions of its habitat, i.e., high salinity, fluctuations in humidity and rapid diurnal temperature changes, as it has another unusual feature, the long, dense white tomentum covering the plant base and root heads; the adaptation also includes manyheaded taproots and probable longevity.

Karyology and sexuality:—The examination of somatic chromosomes (from root tips) of T. mirabile revealed the diploid status, with 2n=16 ( Fig. 4 ). In Taraxacum , according to the numerous records, the diploidy is always associated with sexuality. The sexuality hypothesis is supported also by the perfectly regular size of pollen grains ( Fig. 8E ).

Relationships:—Results of the nrDNA ITS analysis, displayed on Fig. 1 , support a separate position of T. mirabile , along with other remarkable endemics of the eastern Mediterranean region. A detailed morphological comparison shows a number of unique characters, too. Taraxacum mirabile has outer phyllaries very similar to those of T. farinosum of T. sect. Sonchidium , also occurring in the same territory and sharing a few other features with T. mirabile (fleshy leaves, occasionally ± subcartilaginous leaf teeth). However, achenes of these two species are totally different, and T. mirabile cannot be assigned to T. sect. Sonchidium . As regards the achene shape, size and beak length, the closest species is T. primigenium s. str. (Kirschner et al., in prep.) but other achene features (a short broad cone, to select the most conspicuous difference) deviate from the pattern of the T. primigenium achenes.

There are a few taxa that appear to be relatively close to T. mirabile in the Neighbour-Net presentation ( Fig. 1 ). Most of them belong to T. sect. Scariosa Hand.-Mazz., a group very dissimilar from T. mirabile . Another seemingly close taxon is T. glaciale , a very distinctive relictual species of the Apennines, Italy; in terms of morphology, it is substantially different from T. mirabile in all the major structural characters.

The fine sculpture of the achene surface of T. mirabile is unique in Taraxacum . For the sake of comparison, we include SEM images of achene surface of another four taxa belonging to T. section Atrata Kirschner & Štěpánek in Ge et al. (2011: 314; T. chionomelas Kirschner & Štěpánek 2017: 238 ), T. sect. Cucullata van Soest (1959: 120; T. cucullatum Dahlstedt 1907: 25 ), T. sect. Piesis ( Candolle 1838: 145) A. J. Richards ex Kirschner & Stepanek (1993: 297) – T. besarabicum ( Hornemann 1819: 88) Handel-Mazzetti (1907: 26) and T. sect. Borysthenica Kirschner & Štěpánek (2004: 267; T. bachczisaraicum Tzvelev 1986: 258 ), in order to show a selection of mutually very unrelated species. The fine protuberances of the latter four species are firm, acuminate to acute, straight, appressed to erect, of a robust appearance ( Fig. 9 ). The homeologous structures in T. mirabile are thin, not firm, sometimes flexuous, erectpatent to (sometimes) almost patent, subobtuse.

Figures

FIGURE 1. Neighbour-Net constructed from uncorrected P-distances in SplitsTree based on nrDNA ITS sequences of sexual members of 26 Taraxacum sections. The names of the stenoendemic taxa treated in the present paper are marked. The presentation is simplified; details of the analysis are available on request.

FIGURE 2. Distribution of T. mirabile in the Tuz Gölü area, according to the herbarium specimens studied (the base map modified from Google Maps).

FIGURE 3. Taraxacum mirabile; its habitat east of Eskil, with stands of Juncus maritimus dominating the vegetation. Photo B. Gürdal.

FIGURE 4. Taraxacum mirabile. Somatic chromosomes (2n=16); each chromosome outlined (ISTE 116904).

FIGURE 5. Taraxacum mirabile. A field photograph from E. of Eskil, Tuz Gölü, Turkey (photo B. Gürdal).

FIGURE 6. Taraxacum mirabile. General habit (ISTE 116904).

FIGURE 7. Taraxacum mirabile. A, a detail of achene surface; Tuz Gölü (PRA, no. det. 33693). Scale bar = 0.1 mm. B, achenes; Tuz Gölü (PRA, no. det. 33693). Scale bar = 1 mm.

FIGURE 8. Taraxacum mirabile. SEM micrographs of achene surface and pollen. A, achene surface. Scale bar = 100 μm. B, achene surface. Scale bar = 30 μm. C, a detail of achene spinules with hair-like protuberances. Scale bar = 100 μm. D, a detail of achene surface and the hair-like protuberances with waxy gland-like structures. Scale bar = 10 μm. E, pollen grains of ± equal size, an indicator of sexuality. Scale bar = 100 μm. F, a detail of pollen grain. Scale bar = 20 μm.

FIGURE 9. Fine sculpture of achene surface of selected Taraxacum taxa other than T. mirabile, for comparison. A, Taraxacum (Atrata) chionomelas (PRA, cult. JŠ 3835). B, Taraxacum (Cucullata) cucullatum (PRA, cult. JŠ 6575). C, Taraxacum (Borysthenica) bachczisaraicum (PRA, cult. 318). D, Taraxacum (Piesis) besarabicum (PRA, cult. 308). Scale bars: A, 50 μm. B, 20 μm. C, 100 μm. D, 50 μm.