Lachnum rhytismatis

A species occurring on fallen leaves of beech or oak, only up to 0.5 mm in diameter, with distinctive marginal hairs bearing spherical crystallizations.

Marginal hairs hyaline, thin- to moderately thick-walled, septate, 40-60 µm long and 3-4.5 µm wide, crowned by spherical or slightly star-shaped apical masses of calcium oxalate crystals 7-12 µm in diameter.

Asci cylindrical, 8-spored, with biseriate to irregular spore arrangement, 30-45 µm long and 4-5.5 µm wide, apparently lacking basal croziers, with an amyloid apical apparatus in Melzer's reagent.

Paraphyses lanceolate, 3.5-5 µm wide, projecting up to 20 µm above the asci.

Ascospores subcylindrical to slightly fusiform, smooth, hyaline, thin-walled, with homogeneous content devoid of visible guttules or granulations.

Herbarium material available: JTP2070/24 and JTP2414/25.