Umbilicaria platyrhiza Davydov, 2022

Davydov, Evgeny A., 2022, Umbilicaria platyrhiza-a new Mediterranean endemic species of the subgenus Papillophora (Umbilicariaceae, lichenized Ascomycota), Phytotaxa 533 (2), pp. 143-148 : 144

Umbilicaria platyrhiza Davydov , sp. nov. ( Figure 1 , 2 )

MycoBank no. 841496

Similar to U. crustulosa , differing by apothecia with a single gyrus of sterile tissue, grey-brown to black lower surface with flattened to strap-like rhizinomorphs, smaller ascospores, and by producing umbilicaric acid.

Type:— TURKEY. Prov. Izmir (35): southern slope of Yamanlar Dað , small valley N of Karþiyaka, 38°30’ N, 27°07’ E, elev. 125 m, on vertical siliceous rocks. 30 June 2001, V. John [ V. John: Lichenes Anatolici Exsiccati, 171, as U. spodochroa Hoffm. ] (holotype, M!, isotypes examined in ALTB! ex GZU, GZU!, LE L–1933!). Sequences of the holotype: ITS: KY947760 ; RPB2: KY972608 ; mtLSU: KY947904 .

Thallus 2–4 cm in diam. and 0.2–0.3 mm thick, umbilicate, monophyllous. Upper surface pale to dark grey, sometimes with a brown or violet tinge, lighter at the center, minutely rimose, pruinose, more rough and partly radially folded in the center, sometimes with branched to strap-like rhizinomorphs ( Fig. 2C ). Lower surface usually dirty ochre-brown to grey-brown and black, darker towards the center, rimose to coarsely papillate with abundant to scarce rhizinomorphs. Rhizinomorphs simple to few times branched under the sharp angle, often flattened to strap-like, ca. 1 mm long; colored at the base the same as the lower surface, and getting darker toward the tips, with rimose to papillate surface ( Fig. 2A–B ). Thalloconidia absent. Upper cortex paraplectenchymatous, brownish in the outer part and hyaline in the inner part, 25–60 μm, epicortex 12–30 μm, algal layer continuous, 38–100 μm thick, algae Trebouxioid, with cells (5–)7–10–13(–15) μm in diam., medulla colourless, more or less loose, 75–95 μm thick, lower cortex colourless, scleroplectenchymatous, 25–80 μm thick, including a colourless inner layer 20–34 μm thick and a brown outer layer 15–40 μm thick.

Apothecia frequent at the periphery of thalli, ca. 1 mm in diam., disc first flat, with age becoming convex, i.e. broadly cone-like with a single central protruding gyrus of sterile tissue ( Fig. 2D ) with cells 5–9 μm diam. ( Fig. 2E ); epihymenium brown, 13–25 μm thick; hymenium yellowish 65–92 μm thick, hypothecium ochre to light brown, 40–130 μm thick; excipulum inner part yellowish, outer part brown; paraphyses septate, branched, 2.5 μm thick, sometimes slightly thickened at the tips, up to 3 μm; asci 50–60 × 20–30 μm; ascospores hyaline, simple, (14.0–) 16.0–17.5–18.5(–20.0) × (9.0–)9.5–11.5–13.0(–17.5) μm (N=60). Pycnidia at the periphery of thalli, 125–175 μm in diameter, covered by cortex and algal layer, with black prominent ostiole, the wall brown, 10 μm thick, pycnoconidia bacilliform, 3–4×1 μm.

Chemistry: gyrophoric (major), umbilicaric (minor), and lecanoric (minor) acids detected by TLC and HPLC; medulla K–, C+ red, KC+ red, Pd–, UV–.

Etymology: platyrhiza derived from Greek πλατύς – ‘wide, flat’, and ρίζα – ‘root’, with reference to the flattened rhizinomorphs.

Ecology: Umbilicaria platyrhiza grows on siliceous rocks in maritime territories.

Distribution: The species is so far known from only two localities in coastal territories of the Aegean Sea ( Turkey, Izmir) and Black Sea ( Bulgaria, Burgas).

Additional specimens of Umbilicaria platyrhiza examined: BULGARIA. Burgas: loco Veselita skala dicto supra fl. Ropotamo prope inter Sozopol und Primorsko , alt. 30 m s. m. Ad saxa andesitica, 21 August 1977. A. Vežda [Exsicc. Lich. Sel. no. 1531, as U. spodochroa ] ( GZU –324242!, GZU –s.n.!, ALTB! ex GZU) .

Figures

FIGURE 1. Umbilicaria platyrhiza (isotype, GZU): (A) upper surface of mature and juvenile specimens (GZU); (B) lower surface. Bars: A&B=1 cm.

FIGURE 2. Umbilicaria platyrhiza: (A) strap-like unbranched and branched rhizinomorphs; (B) simple, branched, slightly flattened to strap-like rhizinomorphs; (C) branched rhizimomorphs on the upper surface; (D) Apothecia with single prominent gyrus; (E) Section of apothecium; (F) Ascospores. Bars: A–D=1 mm; E=50 µm; F=20 µm.