Hieracium mrazii Szeląg, 2016

Szeląg, Zbigniew, 2016, Hieracium mrazii, Phytotaxa 289 (2), pp. 197-200 : 197-199

Hieracium mrazii Szeląg , sp. nov. ( Fig. 1 )

Type: — ROMANIA. Southern Carpathians , Retezat Mountains , grassy slope on Picea abies forest margin along tourist route from the Râuşor ski centre to the Şaua Ciurila pass, 1620 m a.s.l., 12 August 2013, Z. Szeląg (holotype KRAM; isotypes CL, KRA, Herb. Hierac. Z. Szeląg) .

Paratypes: —Specimens from the living plants collected on the type locality on 12 August 2013 and cultivated in the author’s garden, herbarized on 10 June 2016, Z. Szeląg (Herb. Hierac. Z. Szeląg).

Description: —Phyllopodous. Stem 30–50 cm high, robust, with numerous stellate hairs, dark-based simple hairs (sparse to numerous, 1–2 mm long in the upper part of stem, dense, 4–5 mm long in the lower part of stem). Synflorescence branches with dense stellate hairs and sparse, simple, 1–2 mm long, grey, dark-based hairs. Leaves deep green. Rosette leaves 8–12, overwintering, present at anthesis, subentire to remotely denticulate, more or less sinuate, tapered to a winged petiole, on both surfaces with numerous, soft, 2–3 mm long, simple hairs mixed with stellate hairs, 8–16 cm long and 3–3.5 cm wide; outer leaves obovate, rounded at apex; inner leaves oblanceolate, subacute at apex. Cauline leaves 3–5, gradually reduced upwards, sessile, entire to denticulate, lanceolate or narrowly lanceolate, acute at apex, on both surfaces with sparse, 1–2 mm long, simple hairs and sparse to numerous stellate hairs; uppermost cauline leaf linear, on the upper surface glabrous or almost so. Synflorescence more or less umbellate, with 15–35 erect capitula. Branches 2–4 in nodes of upper cauline leaves, up to 20 cm long. Acladium 3–5 cm. Peduncles grey, covered by dense stellate hairs, numerous, 0.3–0.6 mm long, dark glandular hairs, and a few, 0.7–1.2 mm long, simple hairs. Bracteoles 1–3, linear, covered by dense stellate hairs mixed with simple hairs. Involucres campanulate, ± subglobose at base, (9) 10–11 mm long, covered by moderately dense indumentum. Involucral bracts in three rows; outer bracts squarrose with more or less recurved apices; dark green with pale margins, lanceolate, acute at apex, with numerous, dark-based, 0.8–2.2 mm long, simple hairs, 0.4–0.7 mm long, dark glandular hairs (ratio of simple hairs to glandular hairs ca 1:1), mixed with yellowish microglands and few stellate hairs on margins. Ligules yellow, glabrous at apex. Styles yellow with dark microtrichomes. Achenes black, 3.5–3.7 mm long. Pappus pale-grey. Pollen numerous, spherical and of varying size. Flowering: August.

Affinity: —Morphologically Hieracium mrazii resembles H. umbellatum in (1) a synflorescence umbellate, (2) outer involucral bracts with recurved apices, (3) cauline leaves 3–5, lanceolate and acute at the apex, (4) involucres campanulate, up to 11 mm long. At the same time H. mrazii has some characteristic features of H. transylvanicum , such as: (1) rosette leaves numerous, obovate and rounded at the apex, present at anthesis and overwintering, covered on both surfaces by numerous soft simple hairs 2–3 mm long, (2) a pappus pale-grey.

Distribution and ecology: —Endemic to the Retezat Mountains, Southern Carpathians, known only from the type gathering. It was found on the northern slope of Mt. Fruntea Izvorolui, along a tourist route leading to the Şaua Ciurila pass, at 1600–1650 m a.s.l. The population of Hieracium mrazii was composed of ca. 30–40 flowering individuals growing in a few clusters in the tall-herb community of the alliance Calamagrostion villosae Pawłowski et al. (1928) along the Picea abies forest margin, on granite.

Chromosome number and mode of reproduction: —2n = 4x = 36, agamospermous ( Musiał & Szeląg 2015: 118, as Hieracium sp. ‘Raušor’).

Etymology: —The species name is dedicated to Dr. Patrik Mráz, a Slovak botanist, who produced artificial hybrids between H. transylvanicum and H. umbellatum in experimental crosses ( Mráz & Paule 2006).

Notes:—Both putative parental species are diploid and are widely distributed in the Southern and Eastern Carpathians ( Nyárády 1965). Especially H. transylvanicum plays an important role in the Carpathian woodland phytocoenoses ( Coldea 1991). So far, however, only Pax (1901: 112) announced finding a hybrid between H. transylvanicum and H. umbellatum (not naming it as a separate taxon) based on one specimen ( Pax 1908: 97) collected by him in the Rodna Mountains, Eastern Carpathians, Romania. Zahn (1938) and Nyárády (1965) did not mention this fact.

I was unable to trace the specimen collected by Pax in the Hungarian Natural History Museum in Budapest (BP) which hosts the Carpathian herbarium of Ferdinand Pax, and Natural History Museum in Wrocław (WRSL) where he worked. According to Pax (1908: 97) his specimen differs from H. mrazii in the lack of rosette leaves, whereas H. mrazii has overwintering rosette leaves like H. transylvanicum . The artificial hybrids originated from experimental crosses between H. transylvanicum and H. umbellatum also did not have rosette leaves ( Mráz & Paule 2006).

Sterile F 1 hybrids between H. transylvanicum and H. umbellatum undoubtedly are coming into existence in nature, but their stabilization through apomixis and allopolyploidy ( Asker & Jerling 1992) happens exceptionally rarely. To my knowledge, only one record of spontaneous polyploidization following interspecific crossing in Hieracium s. str. was published ( Mráz et al. 2011).

Figures

FIGURE 1. Holotype of Hieracium mrazii (KRAM).