Cladonia isidiifera 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 : 28-29

Cladonia isidiifera Ahti & Sipman , sp. nov. ( Fig. 3)

Mycobank #MB 803522

Sicut Cladonia ahtii sed differt sorediis absentibus et isidiis cylindricis praesentibus.

Type:— GUYANA. Upper Mazaruni Distr. : E-bank of Waruma R., 20 km S of confluence with Kako R., in ca. 20 m tall, virgin, riverine forest, on overhanging tree along river, ca. 550 m elev., 11 Feb. 1985, H. Sipman & A. Aptroot 18671 (holotype B!) .

Primary thallus persistent, consisting of 1–4 mm long, horizontal to ascending squamules which are deeply divided in ca. 0.5–1.0 mm wide and ca. 0.3 mm thick, slightly crenulate lobes, with flat to concave, green upper side and white or pale brown, shiny lower side, with pale hypothallus, often isidiate along the tips of erect, up to 5 mm long and 2 mm wide extensions of the lobes; isidia short-cylindrical, ca. 0.3 mm long and 0.15 mm wide, glossy. Podetia, conidiomata and hymenial discs not known. Chemistry: barbatic and 4-Odemethylbarbatic (minor) acids. Colour reactions: P–, K–, KC–.

Distribution and ecology:— Known only from a single specimen found in the Upper Mazaruni Distr., Guyana, on an overhanging trunk along a stream at ca. 550 m elev. in mossy forest.

Additional specimens examined:— known from the type only.

Remarks:— The presence of cylindrical isidia is so unusual in the genus Cladonia , that there is no doubt that the only available specimen belongs to an undescribed species. The thallus squamules show that it is related to C. miniata . Morphologically it bears most similarity with C. ahtii . This species is sorediate instead of isidiate, and it lacks the peculiar lobe extensions. In the C. miniata -group there is one more isidiate species, C. caribaea S. Stenroos (1989: 256) . This has coralloid to flattened, not cylindrical isidia.