Pilosella kalinensis Szeląg & Vladimirov, 2025

Pilosella kalinensis Szeląg & Vladimirov , sp. nov.

( Figs. 1–2 View FIGURE 1 View FIGURE 2 )

Type: ― BULGARIA. Rila Mountains , Mt. Golyam Kalin, in the rock crevices on granite ridge, 2620 m a.s.l., 14 August 2019, Z. Szeląg & V. Vladimirov (holotype SOM; isotypes Herb. Hierac. Z. Szeląg) .

Description: ―Phyllopodous. Monocephalous, or with two capitula on erect peduncles, up to 2 cm long, grouped on the top of the stem. Stolons absent. Stem 12–18 cm high, in the lower third with numerous stellate hairs, sparse, pale, black-based trichomes, up to 8 mm long, and sparse, black glands 0.2 mm long; in middle part with numerous stellate hairs, scattered, black in the lower half trichomes, up to 8 mm long, and scattered black glands 0.2 mm long; in the upper third with subdense stellate hairs, numerous black (with grey apex) straight trichomes, up to 10 mm long, and scattered to numerous black glands 0.2–0.3 mm long. Peduncles with dense stellate hairs, dense, black (with grey apex) straight trichomes, up to 11 mm long, and scattered to numerous black glands 0.2–0.3 mm long. Rosette leaves 5–8, up to 9 cm long and up to 1.2 cm wide, lanceolate, entire, acute at apex (the outer leaves shorter and rounded at apex); on upper surface grassy-green with sparse pale simple trichomes 3–4 mm long, scattered to numerous stellate hairs, mixed with sparse yellowish glands 0.3 mm long; on lower surface with protruding pale midrib, and with subdense stellate hairs, only on margins with sparse pale simple trichomes 3–5 mm long and sparse yellowish glands 0.3 mm long. Cauline leaf usually one, up to 1.5 cm long, lanceolate, sessile, acute at apex, with sparse stellate hairs, black-based straight trichomes, up to 5 mm long. Involucres 8.0– 9.5 mm long and 8–10 mm wide, globose at base, with very dense indumentum. Involucral bracts subacute at apex, up to 1.3 mm wide at base, with very dense black (with grey apex) straight trichomes 7.5–10 mm long, scattered stellate hairs, and few dark glandular hairs 0.2 mm long. Ligules warm-yellow, flat or semi-tubular, glabrous at apex. Styles pure yellow. Achenes light brown, 1.8–2.2 mm long. Pappus white. Pollen in anthers quite numerous. Flowering: August.

Ploidy level and mode of reproduction: ―2n ~ 2x ~ 18, sexual.

Distribution: ―Endemic to the Rila Mountains. Besides the type locality on Mt. Golyam Kalin, Pilosella kalinensis was also found on the Mt. Dodov Vrah and Mt. Malyovitsa. Its additional localities on the neighboring peaks higher than 2600 m a.s.l. are to be expected.

Discussion: ―On Mt. Golyam Kalin, Pilosella kalinensis grows with P. rhodopea . They are accompanied by plants with intermediate morphology, mostly triploids and tetraploids and very rare pentaploids, of undoubted hybrid origin. Describing these hybrids as distinct taxa would require cytogenetic studies that are outside our current scope of interest.

Pilosella kalinensis is probably a glacial relict, restricted by the ongoing warming to extreme habitats on the highest peaks, where its small, isolated populations are endangered due to the hybridization with P. rhodopea which benefits from climate change and is increasingly occupying higher altitude areas.

The morphological differences between both species are as follows:

1. Capitula covered with dense, nearly white, twisted, intertwined trichomes up to 5 mm long (on peduncles trichomes sparse to scattered); leaves adaxial surface greyish-green .............................................................................................................. P. rhodopea

2. Capitula and peduncles cowered with very dense, blackish, straight trichomes up to 11 mm long; leaves adaxial surface grassy-green ................................................................................................................................................................................. P. kalinensis Šingliarová & al. (2011) hypothesized that P. alpicola Schultz & Schultz-Bipontinus (1862: 426) has originated as a result of the hybridization between Balkan P. rhodopea and Alpine P. glacialis (Lachenal) Schultz & Schultz-Bipontinus (1862: 426) . In both these species, however, the capitula are covered with pale trichomes (moreover, in P. glacialis the trichomes are sparse and short), while the indumentum on the capitula in P. alpicola consists of long, dense and darker trichomes (https:// www.infoflora.ch/en/flora/hieracium-alpicola.html). The discovery of diploid P. kalinensis suggests that the supposed Balkan parental species of P. alpicola may have been P. kalinensis rather than P. rhodopea .

Notes

Šingliarová & al. (2011: 451) questioned the affiliation of P. breviscapa (DC.) Soják (1971: 218) and P. petraea Schultz & Schultz-Bipontinus (1862: 426) to P. sect. Alpicolinae. This resulted from misunderstanding that the informal rank “aggregate” is only a part of the section and not its equivalent. It was also a mistake to use the name of Hieracium angustifolium Schur (1866: 390) , which belongs to the H. lachenalii agg., as a synonym of Pilosella glacialis ( Šingliarová & al. 2011: 466).