Coniocarpon fallax (Ach.) Grube

The thallus is pale fawn to grey brown and has a matt to weakly glossy, compact surface. It is immersed in the bark to superficial. The margin is not determinate or delimited by a thin brown line, mainly when in contact with other lichen thalli. The photobiont is a species of the family Trentepohliaceae.

The apothecia are raised over the thallus, and are typically elongate or lirellate. They are dark purplish brown in color, and mostly covered in a thick orange red pruina along the apothecial margins and in a thin white pruina on the apothecial disc. Individual lirellae are 0.2–0.4 × 0.1–0.2 mm in size and 65–110 μm tall. They are often aggregated in loose or dense star-shaped clusters reaching 2.5 × 2 mm in size.

The epithecium is 10–20 μm tall, dark brown in color, and includes numerous unpigmented crystals in addition to orange, red and purplish pigmented granules.

The hymenium is 40–75 μm tall and colorless except for an occasional weak and patchily distributed red to purplish pigmentation of the gelatinous matrix.

The hypothecium is colorless or pale brown and 15–30 μm tall.

The paraphysoids are 1–2 μm wide. Their tips are widened to 3–4 μm and extend horizontally above the asci. The tips often protrude from the epithecium to form sparsely branched hair-like extensions up to 15 μm long. The hyphal walls contain patchily distributed brown pigment.

The asci are clavate, with stipe, 50–75 × 20–32 μm in size, and 8-spored.

The spores are colorless, narrow obovate, (15–)17–20 (–22) x (6–) 7–9 (–10) μm in size, and divided by (2–)3–4(–5) transverse septa. The apical cell is enlarged. Old spores are pale brown.

Pycnidia have not been found in the species.

The thallus does not react with C, K, KC, Pd or UV (C–, K–, KC–, Pd–, UV–), but the orange red pruina of the apothecia changes to purple in K (K+ purple). Pigments A1, A2, A3 and A4 in variable amounts have been detected by TLC.

All parts of the apothecia react Idil+ red, I+ red and KI+ blue. A KI+ blue ring structure is present in the tholus of the asci. The orange, red and purple crystals dissolve in K with a clear and fleeting purplish solution.