Arnium hirtum  

Stromata: absent.

Ascomata: 400-700 µm diam, pyriform, the body ± globose, semi-immersed to almost superficial, matt black, covered with flexuous olivaceous mycelial hairs, the neck ± cylindrical, to 500 µm in length, periphysate, often covered with thick-walled rigid cylindrical hairs to 190 µm long and 2.5 µm diam, sometimes with short thin-walled agglutinated hairs at the base of the neck. Peridium membanaceous, composed of three layers; the outer of pale brown irregular rather thin-walled textura angularis with cells to 12 µm diam, the innermost layer composed of ± hyaline flattened cells. Interascal tissue of paraphyses, filiform, thin-walled, sometimes inflated between the septa. Asci 390-420 x 30-50 µm, cylindric-clavate with a long tapering stalk, fairly thin-walled at all stages, the apex rounded to truncate without an apical ring, 4- to 8-spored. Ascospores arranged biseriately, 33-42 x 18-21 µm in 8-spored asci, presumably binucleate spores often also present, 46-52 x 20-24 µm, ellipsoidal to fusiform-ellipsoidal, sometimes slightly inaequilateral, dark brown and thick-walled, smooth, aseptate, with apical and basal germ pores, and tapering elongate apical and basal appendages 35-60(-200) x 7-11 µm, round and hollow in cross-section.

Anamorph: unknown.

Some data taken from Lundqvist (1972).