Taraxacum sect. Bulgarica Štěpánek & Kirschner, 2022

Štěpánek, Jan & Kirschner, Jan, 2022, A hotspot of endemism: Oreophytic Taraxacum species (Compositae, Crepidinae) in the mountains of Bulgaria, Phytotaxa 569 (1), pp. 1-139 : 49-51

C. Taraxacum sect. Bulgarica Štěpánek & Kirschner , sect. nov.

Type:— Taraxacum bulgaricum van Soest (1976: 179)

Diagnosis:—Plantae parvulae, rosulis foliorum compactis, plerumque pusillis, terrae arcte adpressis, petiolis eximie latissime alatis, lobis foliorum lateralibus approximatis, phyllariis involucralibus exterioribus adpressis vel laxe adpressis, ovatis usque lanceolatis, aequaliter obscure olivaceo-viridibus vel atro-viridibus, saepissime peranguste sed distincte marginatis, plerumque ciliolatis, apice ecorniculatis vel callosis, acheniis coloribus diversis, saepe obscure atro-griseis, saturate griseo-brunneis, brunneis, vel e converso, pallidissimis, pallide griseo-cinnamomeis, eburneis etc., corpore superne minute spinuloso, in pyramidem subconicam vel ± cylindricam sensim vel subabrupte transeunte, rostro crassiusculo vel tenui.

Plants small or almost dwarf, most often glabrous, or very sparsely arachnoid and later glabrescent, with leaf rosettes compact, tightly appressed to the ground (immediately reflexed when cut off). Leaves with petioles extremely broadly winged, interlobes very short and lateral segments approximated, relatively broad at base, surface often with little spots. Capitulum ± small, deep yellow to golden yellow, outer ligules usually flat, inner ones canaliculate, apical teeth yellow, reddish or grey to blackish. Outer phyllaries appressed, sometimes loosely appressed, usually (broadly) ovate to ovate-lanceolate, relatively short, surface usually evenly dark olivaceous-green, most often with an abrupt transition into a narrow, relatively distinct paler border, margin usually minutely ciliate, apex flat. Pollen always present.Achenes of medium size, without prominent longitudinal ridges, usually with numerous short spinules above, most often with a subgradual, less frequently subabrupt transition into a conical, subconical or subcylindrical cone; beak relatively short, most often 4–6.5 mm long, pappus white or yellowish white.

Geography and ecology:—The most common natural habitats include low-coverage alpine and subalpine grasslands, often under the influence of grazing or trampling, preferably along brooks and alpine lake shores. Members of this section do not avoid synanthropic alpine sites, such as vicinity of alpine huts and chalets, along tourist tracks, either. They grow on both acidic and alcalic substrates.

Taraxacum sect. Bulgarica exhibits a notably high species diversity in the subalpine and alpine belts of the mountain ranges of Rila and Pirin, a few species are found in the Rhodopes, the Stara Planina and the Vitosha. The occurrence of this section is recorded in other high mountain ranges in the neighbourhood of Bulgaria ( Greece, see Richards, 1991, North Macedonia, as there is a border record on the Belasica Mts.). To the best of our knowledge, we can exclude its distribution in the Carpathians. As an unanswered question remains the occurrence in the Alps but, so far, we do not have any evidence in favour of that idea.

Relationships:—Among the dandelions of high mountains of Europe, there is a group frequently reported to occur in Bulgaria: Taraxacum sect. Alpina , often referred to as T. alpinum s. lat. ( Handel-Mazzetti 1907, van Soest 1976, Doll 1978). There are important, critical accounts of T. sect. Alpina in the Alps ( van Soest 1959, Uhlemann 2011), and it is evident that it is a heterogeneous group, mainly because of the uncertain position of its type. Haglund (1950), when describing his new section Alpina , obviously intended to include a broad Alpine group of high mountain dandelions in it. However, the only name included in the protologue of the new T. sect. Alpina was T. oreophilum G. E. Hagl. , a species very marginal to anything included in T. sect. Alpina in the later literature. However, we can focus our comparison on the members of T. sect. Alpina that are generally considered as core taxa of that section in the literature (e.g., T. panalpinum , T. helveticum , T. petiolulatum , T. venustum [incl. T. carinthiacum ], T. vernelense , T. vetteri ). In the character pattern of T. sect. Bulgarica, the following features appear to be diagnostic, when compared with the core members of T. sect. Alpina:

Leaf rosette compact, with leaves tightly appressed to the ground, petiole enormously broadly winged, lateral leaf segments approximated (interlobes very short), outer phyllaries usually ovate, ovate-lanceolate or lanceolate, with a narrow whitish border, their margin usually ciliate, achene colour usually deviating from the light greyish stramineousbrown or light greyish olivaceous-brown pattern of other sections, they are often deep grey to dark grey or deep greybrown (seven species), or they have much paler colour, light beige, ivory white, light brownish with an orange hue, light beige with a cinnamon hue (six species with the pale achene colours), or pure brown.

Note:—There are two species of T. sect. Alpina, T. mattmarkense van Soest and T. senile van Soest (1966: 458) , having broadly winged petioles. They differ from T. sect. Bulgarica in their robust growth with erect-patent leaves, in comparatively longer outer phyllaries and thicker achenes.

Another section to be compared with T. sect. Bulgarica is T. sect. Pachera van Soest, obviously a part of the broadly understood T. sect. Arctica. The latter has patent to erect-patent leaves, not tightly appressed to the ground, medium broadly winged petioles, much narrower than leaf blade, and black-green, narrowly lanceolate, lanceolate or ovate-lanceolate acuminate outer phyllaries, without visible border. It has orange-coloured ligules or their distal parts, and its achenes are light greyish olivaceous-brown or light greyish stramineous-brown, very sparsely tuberculate or sparsely minutely spinulose above, with a very gradual transition into a ± conical to subconical cone; its beak is slightly thickened, not longer than the achene.

Taraxacum sect. Arctica Dahlstedt (1921: 37) is one of the groups close to our T. sect. Bulgarica. There are several substantial diagnostic features of T. sect. Arctica compared with T. sect. Bulgarica, primarily the narrow petioles, and outer phyllaries few, of broader shapes (most often broadly ovate to ovate), often with apex corniculate.

Diversity:—In T. sect. Bulgarica, we recognize 18 species, one already described ( T. bulgaricum ) and 17 newly discerned. Most of the members of T. sect. Bulgarica are morphologically allied to the only sexual representative of this section, T. bulgaricum ( T. ferum , T. auricula , T. humifusum , T. vitellicolor , T. oreades , T. terrestre , T. atomatum , T. tephroleucum , T. pseudobulgaricum , T. saevum , T. musalae and T. melanospilum ), altogether 13 species that form the core of T. sect. Bulgarica. It might be mentioned that artficial hybrids between T. bulgaricum and a sexual member of T. sect. Taraxacum , T. linearisquameum , have a general appearance similar to that of the members of T. sect. Bulgarica (J. Štěpánek, unpublished), which might help in formulating hypotheses about their origin. Taraxacum circense (and partly also T. tephroleucum and T. terrestre ) may be intermediate between T. sect. Bulgarica and T. sect. Crocea but much closer to the former. A rather enigmatic group of T. pirinicum , T. leopardinum and T. abnorme is referable to T. sect. Bulgarica only marginally.Another name to be considered is T. bithynicum Candolle (1838: 149 ; see Gürdal et al. 2018), and a very questionable position, as regards the relationships with T. sect. Bulgarica, is occupied by T. nudum van Soest (1976: 187) .

An identification key to the Bulgarian members of Taraxacum sect. Bulgarica

1 Pollen grains regular, of ± uniform size ............................................................................................... 11. T. bulgaricum van Soest

– Pollen grains irregular, of conspicuously variable size .................................................................................................................... 2

2 Outer phyllaries unbordered, at least some erect-patent and patent, 18–23, leaves not spotted; beak usually 7–9.5 mm long .......... ................................................................................................................................................................. 14. T. humifusum , sp. nov.

– Outer phyllaries variously, usually narrowly and distinctly bordered, all appressed to loosely appressed, 9–17, if 18–20, or if some outer phyllaries arcuate, then leaves distinctly spotted, or beak shorter than 6 mm ........................................................................ 3

3 Stigmas yellow ................................................................................................................................................................................. 4

– Stigmas light discoloured to dark discoloured ................................................................................................................................. 5

4 Achenes light pure brown or medium deep grey-brown; leaves appressed to the ground, shallowly pinnatilobed or undivided; cone 1.0– 1.1 mm long ........................................................................................................................................... 13. T. auricula , sp. nov.

– Achenes light stramineous to light stramineous-brown; leaves erect-patent to prostrate, deeply irregularly pinnatisect; cone to 0.9 mm long ....................................................................................................................................................... 27. T. abnorme , sp. nov

5 Achenes ivory white or slightly, pale greyish white; leaves adaxially with sparse brownish hairs along mid-vein ........................... .............................................................................................................................................................. 19. T. tephroleucum , sp. nov.

– Achenes either much darker, deep grey, brown-grey or brown, or light beige, light stramineous-brown or light greyish brown; leaves adaxially glabrous or with sparse hyaline or whitish arachnoid hairs ................................................................................... 6

6 Achenes of generally dark colours, deep grey or deep brown-grey or medium dark brown-grey, or medium dark pure brown or dark castaneous-brown, achenes medium thick, usually 0.9–1.2 mm wide; leaves spotted .................................................................... 7

– Achenes of generally light colours, variously light beige, light stramineous, light beige-brown, if light pure grey or light greybrown, then achenes slender, 0.7–0.9 mm thick; leaves spotted or unspotted ............................................................................... 11

7 Outer phyllaries with a narrow border 0.1–0.2 mm wide; outer phyllaries 10–15; achene body gradually, subgradually or subabruptly narrowing into the cone .................................................................................................................................................................... 8

– Outer phyllaries with a medium broad border 0.2–0.5 mm wide; outer phyllaries 15–20; achene body abruptly or subabruptly narrowing into the cone .................................................................................................................................................................. 10

8 Achenes medium dark grey-brown; leaves appressed to the ground; outer phyllaries 4–6 mm long .............................................. 9

– Achenes medium dark pure brown or dark castaneous-brown; leaves usually erect-patent; outer phyllaries 5–6 mm long ............. .................................................................................................................................................................... 28. T. pirinicum , sp. nov.

9 Outer phyllaries loosely appressed; stigmas light discoloured; beak slightly thickened, 4.5–5.5 mm long ....................................... .......................................................................................................................................................20. T. pseudobulgaricum , sp. nov.

– Outer phyllaries tightly appressed; stigmas dark discoloured; beak thin, 5.5–7.5 mm long ................ 22. T. chionogeiton , sp. nov.

10 Outer phyllaries usually 3.5–4 mm wide, ovate to ovate lanceolate; beak usually 7–8.5 mm long, slightly thickened; leaves deep mid-green, sparsely spotted ................................................................................................................ 24. T. melanospilum , sp. nov.

– Outer phyllaries usually 2–3 mm wide, lanceolate to broadly lanceolate; beak usually 4–6 mm long, not thickened; leaves light green or yellowish green, conspicuously, densely spotted ........................................................................... 23. T. musalae , sp. nov.

11 Leaves variously erect-patent to patent, not prostrate, nor appressed to the ground; .................................................................... 12

– Leaves appressed to the ground or prostrate .................................................................................................................................. 13

12 Achenes slender, 0.9–1.0 mm thick; leaves inconspicuously and sparsely spotted; outer phyllaries with a narrow membranous border 0.1–0.2 mm wide ............................................................................................................................... 25. T. circense , sp. nov.

– Achenes thick, 1.2–1.4 mm wide; leaves conspicuously and densely spotted; outer phyllaries broadly bordered, with contrasting colours of the dark middle part and pale greenish to whitish, ca. 0.5 mm wide zone bordered irregular membranous, 0–0.3 mm ... ............................................................................................................................................................... 26. T. leopardinum , sp. nov.

13 Outer phyllaries with contrasting colours of a dark middle strip with a gradual transition in pale greenish zone to ca. 0.5 mm wide and then to a membranous border 0.1–0.2 mm wide; outer phyllaries short, 3.5–4.5 mm long, appressed ....................................... ................................................................................................................................................................... 15. T. vitellicolor , sp. nov.

– Outer phyllaries ± evenly dark coloured, with an abrupt or ± gradual transition into a narrow pale or membranous border 0.05–0.2 mm wide; when the border to ca. 0.3 mm wide and outer phyllaries 4–5 mm long, at least some phyllaries arcuate .................. 14

14 Achenes light beige, light greyish beige, light beige-brown, light greyish ochraceous, generally very light coloured ................. 15

– Achenes light brown to slightly greyish light brown, or pure light grey or light brownish grey, with grey dominating the achene colour .............................................................................................................................................................................................. 17

15 Outer phyllaries mostly loosely appressed, some arcuate; outer phyllaries short, 4–5 mm long, narrow, 1.5–2.5 mm wide; achenes 3.6–4.1 mm long; leaves light green, not spotted .......................................................................................... 21. T. saevum , sp. nov.

– Outer phyllaries appressed or loosely appressed, never arcuate; outer phyllaries longer, 4.5–7 mm long, broader, (2.2–) 2.5–3.5 mm wide; achenes (3.9–) 4.2–5.6 mm long; leaves dark green to deep green, sparsely, conspicuously or inconspicuously spotted ......................................................................................................................................................................................................... 16

16 Petiole pale at base, ± purple distally; leaves sparsely but conspicuously spotted; beak 5.5–6.5 mm long ....................................... .................................................................................................................................................................... 18. T. atomatum , sp. nov.

– Petiole entirely light greenish; leaves sparsely indistinctly spotted; beak 6.5–7.5 mm long ........................... 12. T. ferum , sp. nov

17 Achenes 1.2–1.4 mm thick, light brown to slightly greyish light brown; lateral segments generally patent 16. T. oreades , sp. nov.

– Achenes 0.7–0.9 mm thick, light pure grey to slightly brownish light grey; lateral segments generally hamate-recurved ............... ....................................................................................................................................................................... 17. T. terrestre , sp. nov.