Quercus protoroburoides Donchev & Bouzov ex Tashev & Tsavkov, 2017

Tashev, Alexander & Tsavkov, Evgeni, 2017, Validation of the name Quercus protoroburoides (Fagaceae), Phytotaxa 308 (2), pp. 232-238 : 233-236

Quercus protoroburoides Donchev & Bouzov ex Tashev & Tsavkov , sp. nov. ( Fig. 1 )

Diagnosis:— Quercus protoroburoides is morphologically closest to Quercus hartwissiana . However, it differs by the latter in the longer petioles (ca. 21 mm in Q. protoroburoides and ca. 17.7 mm in Q. hartwissiana ), shorter fruitstalks, variable trichomes and thicker cuticle of the leaf-lamina.

Type :— BULGARIA, Rila Mountains , river Drushlyavitsa (right-hand tributary of river Rilska), 1675 m, 42 o 08′44.8ʺN, 23 o 10′10.1ʺE, 03 September 2015, Alexander Tashev & Evgeni Tsavkov (holotype: SOM 172670 ; Fig. 1 ) .

Habitus:Arbor decidua altitudine ad 25m et diametro ad 80 cm; caulis comparate regulariter ramosus,fere monopodialis; cortex profunde rimosus, sulci ad 2 cm profundi. Ramuli annui brunneoli, crassi, angulati, in fine periodi vegetationis glabri vel pilis griseo-brunneis pilosi, lenticellis lucidis ellipsoideis tecti. Gemmae sphaericae usque ad ovatas, apicales valde grandes— 4–8 mm, apice semper rotundatae, pilosae, cum stipulis planis partim persistentibus cum apice adunco; squamae gemmarum late ellipsoideae, apice rotundatae, brunneolae, pilosae. Lamina obovata usque ad ellipsoideam, comparate magna, longitudine 7.0–15.0 cm et latitudine 5.0–7.0 cm, cum 5–9 (11) lobis rotundatis non profunde incisis, cum nervis lateralibus fere parallelicis (sub angulo 35–45°), nervi intercalares fere absunt, superne atro-virides, lucentes, inferne pallide virides, pilis stellatis vel fasciculatis raro locatis tecti; basis laminae auriculariter incisa. Petiolus longitudine (1.3) 2–3.2 (4.0) cm, parce pilosus, sectione transversali semiteres. Flores unisexuales, monoecialiter collocati; flores masculi cum perianthio 5–7 lobato fere ad basim excise, stamina 8–9, cum pedicellis 1–1.5 mm; flores feminei cum perianthio 6–7 lobato, valde pilosi, styli 3–5, liberi vel coaliti ( Fig. 3 D ). Pedunculus bene evolutus, parce pilosus longitudine ad 6–7 cm et crassitudine 1.7–3.0 mm. Glandes singulae vel binae (raro ad 5–6) in pedunculo communi collocatae, doliiformes vel cylindricae, longae ad 3.5 (1.5–3.5) cm et latae ad 2 (0.7–2.0) cm, cupula crassitunicata diametro 1.5–1.7 cm, amplexa 1/4 ad 1/3 glandis; endocarpium glabrum. Floret simulatque frondescit fine mensis Maji et initio mensis Junii (V–VI); fructus maturescunt (fructificat) mense Septembre–Octobre (IX–X). Distributio et habitatio: Rila mons—in systemate “Rilska reka”, in locis “Kalugerski dol”, “Pavlov dol”, “Brichebor”, “Drushljavitsa” et supra pagum Pastra, in declivitate supra ripam dextram fluminis “Eleshnitsa”, inter 1500–1700 m supra mare in valde arduis et petrosis locis (declinatione ad 40–45°), dispositione meridionali. Limitem superiorem silvae in nonnullis locis format, singulae arbores ad 1750 m supra mare ascendunt, sed sub 1550 m supra mare paulatim cum specie Quercus dalechampii miscetur. Monodominantes associationes imprimis format atque in compositione associationum mixtarum cum speciebus Fagus sylvatica , Pinus sylvestris , Picea abies , Populus tremula , Acer hyrcanum , A. platanoides , Sorbus aria , Corylus avellana , Rosa canina , Rubus idaeus , Chamaecytisus absinthioides , Fraxinus ornus , Cotoneaster integerrimus , Ulmus glabra , etc. participat. Endemita localis. Relictum tertiarium.

Affinitas: Species ad Sect. Robur Reichenbach (1831: 177) .

Etymology: The species epithet “protoroburoides ” was originally proposed by Donchev & Bouzov (1981), which expresses the authors’ opinion that this species most probably is ancestral to the oaks from section Robur , having in mind the geographic isolation of the locality, as well as the presence of morphological characteristics typical for a big number of roburoid oaks.

Vernacular name:—Рилски дъб (Rilski dab) (Bulgarian).

Key: —To distinguish Quercus protoroburoides from the other roburoid oaks in Bulgaria, an identification key is provided (based on Schwarz 1993 and Uzunova & Palamarev 1992).

Figures

FIGURE 1. Holotype of Q. protoroburoides (SOM 172670).

FIGURE 3. A.Abaxial epidermis in Q. protoroburoides with three types of trichomes: glandular, star-like (2–4 ray) and bunch trichomes, in Brichebor locality; B. Abaxial epidermis in Q. protoroburoides: star-like and bunch trichomes, in Pavlov Dol locality; C. Abaxial epidermis in Q. protoroburoides: 4-ray star-like trichomes coalesced asymmetrically 2 × 2 into a scale; D. Shape of the gynaeceum styles in Q. protoroburoides;