Cladonia recta Ahti & Sipman, 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 : 34-35

Cladonia recta Ahti & Sipman , sp. nov. ( Fig. 7 )

Mycobank # MB 803524

Sicut Cladonia peltastica sed podetiis gracilioribus albo-cinereis; conidiomata gelatinam purpuream continentia; acidum squamaticum continens.

Type:— GUYANA. Upper Takutu Distr. : ca. 35 km S of Aishalton, ca. 5 km N of Kuyuwini Landing, along track to Karaudanawa, ca. 2°08'N, 95°15'W, ca. 250 m elev., on sandy soil among scattered shrubs and trees along and on small savanna, 1 Nov. 1992, H. Sipman 57134 (holotype B 60 0164014!, isotype BRG!) .

Primary thallus evanescent, consisting of very small, to 0.2 mm long, slightly crenulate squamules. Podetia 2– 5 cm tall, 0.2–0.5(–1) mm thick, of indeterminate growth, whitish grey, basal parts darker but not melanotic, extreme tips black, forming dense mats with individual podetia erect and very straight, branched by irregular anisotomous dichotomy, rarely trichotomy, main stems distinct but somewhat anastomosing, equally thick; axils normally closed but occasionally perforated; tips erect or slightly bent, acuminate. Podetial surface continuously corticate, cortex smooth or somewhat rugulose, especially towards the base, occasionally slightly squamulose, dull to slightly shiny, somewhat maculate, with some brownish, ecorticate patches near the base; soredia lacking. Podetial wall anatomy not studied; stereome distinct, central canal very narrow. Conidiomata on tips of podetia, ca. 200 × 100 µm, cylindrical, not constricted at the base, black, containing purple slime. Hymenial discs at tips of slightly swollen podetia, very small (ca. 0.1 mm diam.), pale brown; spores not observed. Chemistry: squamatic acid. Colour reactions: P–, K–, KC–.

Distribution and ecology:— As far as known a Guianan endemic, collected only in Guyana on sandy soil and rotten wood in savanna, at ca. 250 m elev.

Additional specimens examined (paratypes):— GUYANA. Upper Takutu Distr. , ca. 35 km S of Aishalton, ca. 5 km N of Kuyuwini Landing, along track to Karaudanawa, ca. 2°08'N, 95°15'W, ca. 250 m, Sipman 57127, 57132 (B!, BRG!) .

Remarks:— Cladonia recta resembles most C. peltastica , but is much more slender and forms conspicuous, straight, erect colonies. However, it is possible that it represents an usnic acid-free chemotype of that species.

Figures

FIGURE 7. Cladonia recta, holotype. Bar = 2 cm.