Perigrapha phaeophysciae Etayo & Pérez-Vargas, 2013

Pérez-Vargas, Israel, Etayo, Javier & Hernández-Padrón, C., 2013, New species of lichenicolous fungi from the Canary Islands, Phytotaxa 99 (2), pp. 58-64 : 62-63

Perigrapha phaeophysciae Etayo & Pérez-Vargas , sp. nov. ( Fig. 3 ) MycoBank MB 800607

Similar to P. superveniens but differs in smaller asci and smaller ascospores, as well as the absence of appendages in the ascospores and a different host ( Phaeophyscia ).

Type:— SPAIN. Canary Islands: La Palma, Los Sauces, “Almácigo de San Andrés”, small forest of Pistacia atlantica Desf. , ca. 100 m, on Phaeophyscia cf. orbicularis , on stones, 29 July 2000, J. Etayo & P.L. Pérez de Paz 17580 (holotype TFC-Lich!; isotype herb. Etayo!).

Ascomata stromatic, superficial on the thallus of Phaeophyscia cf. orbicularis , sometimes several stromata are confluent, black, rounded, with regular margin, flattened, (0.25–)0.5–0.75(–1) mm diam. Surface riddled with small granula corresponding to the ostioles of the loculi. Stroma multilocular, ca. 200 µm thick. Sterile stromatic tissue greenish brownish to blackish, K+ greenish intensifying. Loculi 70–100 µm diam. Below the loculi there is a hyphal net with greenish to brown cells 3–4 µm thick, intermixed with dead algae, with a total thickness of 30–100 µm. Hymenium hyaline to pale greenish, I+ red, KI+ blue, 70–90 µm high; epihymenium hyaline to pale brown or greenish. Paraphyses branched and anastomosed, septate, 1–1.5 µm thick, sligthly capitate, apically up to 2 µm. Asci fissitunicate, clavate, apically thickened, with an ocular chamber, 6–8 spored, 39–41 × 10–13 µm, with a small K/I+ blue apical ring. Ascospores hyaline, 3–septate, not or hardly constricted at the septa, with one large or several smaller oil guttules in each cell, (12–)13–18 × 4–5 µm (n=25); perispore ca. 1 µm in young spores, indistinct in matures ones, without apical appendages; brown pigmentation not observed. Pycnidia intermixed with loculi; wall of the same structure; conidiogenous cells lining the conidial wall, ampulliform, ca. 6 × 2.5 µm. Conidia bacillar, straight, hyaline 3–5.5 × 0.5–0.8 µm (n=25).

Etymology:— The epithet phaeophysciae refers to the host lichen genus Phaeophyscia Moberg.

Distribution and ecology:— Perigrapha phaeophysciae is so far known only from the type locality in La Palma (Canary Islands) growing on Phaeophyscia sp. , on rocks in a shaded area.

Discussion:— In accordance with the delimitation by Hafellner (1996), we consider this species as belonging to the genus Perigrapha Hafellner , as it has the typical stromata with perithecioid loculi and a punctiform ostiole, asci with a small ocular K/I+ blue ring, branched and anastomosing paraphyses, and hyaline and 3–septate ascospores. Although Hafellner (1996) described the spores with long caudate appendages at one end, Ertz et al. (2005) enlarged the genus concept with a species with ascospores lacking such appendages.

Perigrapha phaeophysciae differs from the type species, P. superveniens (Nyl.) Hafellner in the absence of those appendages, and in the size of the ascospores (30–35 × 4.5–6 µm vs (12–)13–18 × 4–5 µm in P. phaeophysciae ) and asci (80–100 × 12–15 µm vs 39–41 × 10–13 µm in P. phaeophysciae ). Futhermore, P. superveniens grows on Parmelia sulcata Taylor ( Hafellner 1996) . Perigrapha nitida Ertz et al. , described on Pseudocyphellaria glabra (Hook. f. & Taylor) C. W. Dodge from Australia and New Zealand differs from P. phaeophyciae in ascomatal size (0.1–2.5 mm diam.), 4–spored and larger asci (50–75 × 9.5–12), and larger ascospores (15.5–) 18–24.5 × 3.5–6 µm (Ertz et al. 2005). Perigrapha phaeophysciae resembles Opegrapha phaeophysciae R. Sant. et al. described on the same host genus (Ertz et al. 2005), but the latter has deep cracks in the ascomata with a raised and marginal exciple. In addition, O. phaeophysciae has 4–spored, larger asci (40–60 × 10–16 µm), and larger ascospores 21.5–28(–38.5) × 3.5–6(–7) µm, with a granulose and brown pigmentation. This is the first time pycnidia have been reported in the genus.

Figures

FIGURE 3. Perigrapha phaeophysciae, holotype. A-B. Habit; scale: 1 mm. C. Section through multilocular stroma; scale: 100 µm. D. Ascus with ascospores; scale: 25 µm. E. Ascospores; scale: 10 µm.