Calycina citrina

General description: 

Asexual morph not known.
Ascomata apothecia, often aggregated in swarms, 0.5-2.5 mm diam., erumpent from bark, shallowly cup-shaped with a slightly concave disc, bright yellow, very shortly stipitate. Outer wall of apothecium pale to bright yellow, smooth, the outer layer composed of parallel to slightly interwoven hyphae with thick refractive walls. Interascal tissue of filiform paraphyses 1-2 µm diam., somewhat swollen at the apex and ocntaining minute bright yellow oil globules. Asci 75-135 x 8-10 µm, cylindrical, the apex rounded, with a weakly blue-staining apical ring, 8-spored. Ascospores arranged obliquely uniseriately to biseriately, 9-14 x 3-5 µm, ellipsoidal, hyaline, sometimes eventually becoming 1-septate, thin-walled, smooth, without a gelatinous sheath.

Description adapted in part from Dennis (1956).

Conservation status: 

Not formally assessed, but very common and certainly not in any of the threatened categories.

Associations: 

On rotten wood, especially of Fagus but also other hardwoods such as Corylus and Fagus; presumably saprotrophic.

Distribution: 

Throughout Britain and Ireland.

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith