Nemania confluens











Nemania confluens (Tode: Fr.) Laesse & Spooner.

Stromata fully immersed to nearly superficial, typically uniperitheciate but often coalescent in linear rows or in small groups with up to 5 (-10) perithecia beneath a carbonaceous outer stromatal layer 130-150 m thick extending into the substrate, subglobose, dark brown to dull black, 0.6-1 (-1.7) mm diam, frequently with a flattened apex, when young emerging from a copious white hyphal tissue; interperithecial tissue greyish, soft, inconspicuous.

Perithecia subglobose, 0.5-0.8 (-1.2) mm diam.

Ostioles minutely papillate, black.

Asci cylindrical, short-stipitate, the spore-bearing parts 105-125 m long x 10-12 m broad, the stipes 25-40 m long, with apical apparatus amyloid, cuboid to inverted hat-shaped, 2.5-3 high x 3-4.5 m m broad.

Ascospores 15-18 x 8-9.5 m, dark brown, ellipsoid nearly equilateral with narrowly rounded ends, uniseriate in the ascus, with a conspicuous straight to slightly sinuous germ slit spore-length on the less convex side when ascospore is inequilateral.

Specimens examined: FRANCE: Arige (09): Rimont, Las Muros, 15 Jun. 1995, JF-95005, on Quercus robur; Rimont, Las Muros, ruisseau de Peyrau, 09 Aug. 1998, JF-98099, on Quercus robur; Rimont, Las Muros, 06 May 2001, JF-01086, on Corylus avellana; Prat Communal, ruisseau de Loumet, 1000 m elev., 02 Jul. 2001, JF-01135, on Abies alba. Dordogne (24): Lalinde, Courcelles, 25 Dec. 1999, JF-99294, on Robinia pseudoacacia. Haute Garonne (31): Couladre, ruisseau de Tounis, 18 Jan. 2003, JF-03012, on Quercus robur.

Notes: Nemania confluens is distinctive among other Nemania taxa in having uniperitheciate stromata usually partially immersed in the substrate, short-stipitate asci with a cuboid apical apparatus and nearly equilateral ascospores. Granmo et al. (1999) assume it should be removed from Nemania.

In the field, it may be easily confused with the small stromata of Euepixylon udum (Pers.: Fr.) Laesse & Spooner, an other xylariaceous fungus which also grows more or less immersed in very rotten wood of Corylus and Quercus. Ascospores of E. udum differ from those of N. confluens in being much longer, averaging 25-27 m long, paler, with broadly rounded ends and a poroid germ slit.

Nemania confluens is so far known from Europe [Miller, 1961 (as Hypoxylon confluens); Dennis, 1978 (as Hypoxylon semiimmersum); Petrini and Mller, 1986 (as Hypoxylon confluens); Granmo et al., 1999], but also reported by Ju and Rogers (2002) from Chile and U. S. A. It is not uncommon, and always found on very rotten decorticated sapwood, most often of Corylus and Quercus, but appears to be plurivorous, as pointed out by Miller (1961) and Granmo et al. (1999). A collection on a small dead standing rotten trunk of Abies alba (JF-01135) is noteworthy as Nemania taxa are very rarely recorded on Gymnospermous wood (Granmo et al., 1999).