Cladonia persphacelata Sipman & Ahti, 2013

Ahti, Teuvo & Sipman, Harrie J. M., 2013, Ten new species of Cladonia (Cladoniaceae, Lichenized Fungi) from the Guianas and Venezuela, South America, Phytotaxa 93 (1), pp. 25-39 : 32-34

Cladonia persphacelata Sipman & Ahti , sp. nov. ( Fig. 6 )

Mycobank # MB 803523

Sicut Cladonia sphacelata , sed podetia cornea, fusca, incrassata, squamulis elongatis; acidum didymicum et acidum thamnolicum continens.

Type:— GUYANA. Upper Mazaruni Distr. : Mt. Latipu, ca. 8 km N of Kamarang, at ca. 1000 m elev., in scrub on summit plateau, on white sand on open spot, 25 Feb 1985, H. Sipman & A. Aptroot 19149 (holotype B!, isotype BRG!) (TLC: thamnolic, tr. didymic acid) .

Primary thallus persistent to evanescent, consisting of up to 0.5 cm long squamules which are deeply divided into ca. 0.5 mm wide, elongate laciniae, attenuated and often almost stalk-like at the base, on the lower side with rather smooth surface to corticoid and sometimes with ochraceous streak. Podetia up to 5 cm tall and 0.5–1.5 mm thick, of determinate growth, grey to usually more or less brown, in lower part almost black, horny and swollen, somewhat branched; branching type irregular anisotomous dichotomy, rarely trichotomy or tetrachotomy; axils closed or with usually small openings; tips often divided into 2–10 short branchlets. Podetial surface smooth and often shiny, denudated even at the tips, finally being rather densely squamulose, smooth inbetween, esorediate; mature squamules narrow, laciniate and imbricate, up to 4 mm long, pointing downward but with recurved tips, often glossy. Podetial wall 200–290 µm thick; cortex (0–) 25–40 µm, consisting of large cells; medulla very thin, (0–) 10–25 µ m (including the algae); stereome distinctly delimited, very horny, thick, 200–250 µ m, inner surface glossy. Conidiomata terminal on tiny apical branchlets, often grouped, 200–250 × 100–150 µm, dolioliform, constricted at the base, shortly pedicellate, containing red slime. Hymenial discs not seen. Chemistry: thamnolic acid sometimes with a trace of didymic acid (TLC of 6 specimens). Colour reactions: P+ yellow, K+ yellow, KC–; UV –.

Distribution and ecology:— A Guayana Highland endemic, known only from Venezuela and Guyana. It is widespread in the Guayana Highland of Venezuela in light, mossy forest over sandstone at ca. 600–1100 m elev. In Guyana found on mossy sandstone rocks in light forest, rather shade-tolerant and avoiding open spots, from 400 to 1000 m elev.

Additional specimens examined (paratypes):— GUYANA. Upper Mazaruni Distr. , 2 km N of Kamarang, 500 m, Sipman & Aptroot 18241 (B!); E-bank of Waruma R ., ca. 20 km S of confluence with Kako R. (campsite 4) , Sipman & Aptroot 18241, 18660 (B!); trail from Kamarang R . to Pwipwi Mt., ca. 10 km N of Waramadan, Sipman & Aptroot 19322, 19494 (B!); Potaro-Siparuni Region, Kaieteur Falls National Park, around the airstrip, Sipman 40447 (B!, BRG!); Region 7 ( Upper Mazaruni Distr. ), N of Paruima Mission, Aymatoi savanna, Sipman 39860 (B!, BRG!, US!) ; Cuyuni-Mazaruni Region, Partang R ., 8.6 km NE of Imbadamai, Hoffman 1722 (H!) . VENEZUELA. Bolívar: Cerro Guaiquinima, in central part of upper plateau, along Río Carapo (near camp 3-nuevo), Sipman 27065 (B!, H!, VEN!); in central part of upper plateau (near camp 4), Sipman 26487 (B!, VEN!); near NE edge of upper plateau (near camp 2), Sipman 26890 (B!, VEN!); near west end of upper plateau (near camp 5), Sipman 27102 (B!, H!, VEN!); Canaima, at Río Carrao , Sipman 27256 (B!, VEN!) .

Remarks:— Cladonia persphacelata belongs to a group of closely related species including in the Guianas C. polystomata Ahti & Sipman in Ahti (2000) and C. subsphacelata (see below), and the Brazilian C. sphacelata Vainio (1887: 456) . C. polystomata grows on soil or litter and forms wide funnels on top of more or less corticated, up to ca. 1 cm thick, little branched podetia with short squamules. C. subsphacelata has largely corticate, less than 1 mm wide podetia, and shares with C. persphacelata the saxicolous habit and very elongated squamules. C. sphacelata has short podetial squamules, the podetia remain thin, under 1 mm wide, and do not become horny.

Richly squamulose forms of C. subdelicatula Vainio ex Asahina (1963: 1) can also resemble C. persphacelata . They differ by their felty rather than smooth surface and their preference for tree bark as substrate (in the Guianas).

Figures

FIGURE 6. Cladonia persphacelata, holotype. Bar = 2 cm.