Glaucomaria

Glaucomaria is a genus of lichen-forming fungi in the family Lecanoraceae. It has seven species. The genus was circumscribed by Maurice Choisy in 1929. It contains crustose lichens formerly placed in the Lecanora rupicola species complex as defined by several previous authors.

Description
Glaucomaria is characterised by a crust-like (crustose) thallus, which is sometimes spread out with a radiating pattern. The colour of the thallus ranges from white-yellowish green to pale grey. The apothecia (fruiting bodies) initially grow attached and can become slightly raised  or nearly stalked (substipitate). These apothecia feature a heavily powdery  that reacts to the C spot test to produce an intense lemon-yellow colour. The margin of the apothecia is persistent, sometimes being pushed aside (finally excluded), and occasionally surrounded by a black, wavy ring.

The outer layer of the apothecia typically has a  cortex (containing hyphal fragments and dead, collapsed algal cells), numerous algal cells, and both large and small crystals, with the latter dissolving in a solution of potassium hydroxide (K). The inner layer ranges from thin to thick, dark on the outside and upper part but colourless inside. The (topmost layer of the apothecia) is brown to dark brown with crystals, both the pigment and crystals dissolving in K. The hymenium, the spore-producing layer, is colourless and does not contain oil droplets. The paraphyses (sterile filaments in the hymenium) are slightly thickened at the top. The layer below the hymenium is colourless and not interspersed with droplets.

The asci (spore-bearing cells) of Glaucomaria are club-shaped and very thin-walled. They contain a tall structure in the middle that reacts to iodine and potassium hydroxide by turning blue (K/I+ blue), surrounded by a blue outer layer (Lecanora-type). The are single-celled, hyaline (translucent), ellipsoid, and have a wall less than 1 μm thick. The, the photosynthetic partner of the lichen, is a type of green algae (chlorococcoid).

Chemistry
Glaucomaria contains a variety of compounds including arthothelin, atranorin, chloroatranorin, eugenitol, isoarthothelin, and methyl 3a-hydroxy-4-O-demethylbarbatate. Some species also have sordidone, psoromic acid, thiophanic acid, dichlorlichexanthone, and 2,5,7-trichlornorlichenxanthone. The pruina (powdery substance) on the apothecial disc contains sordidone and occasionally thiophanic acid.

Species

 * Glaucomaria bicincta
 * Glaucomaria carpinea
 * Glaucomaria leptyrodes
 * Glaucomaria lojkaeana
 * Glaucomaria rupicola
 * Glaucomaria subcarpinea
 * Glaucomaria swartzii