Genus
Sarcogyne includes lichens with a crust-like (
crustose)
thallus that can be cracked into small, island-like sections called , which are either broadly attached or have a thick fungal base. Sometimes, the thallus is , meaning it has small, scale-like structures with a stalk less than half the width of the scale. The upper surface, or , of these lichens can vary from absent to quite thick and often gives the lichen a shiny appearance, especially in species found in dry or hot habitats. This shiny layer is particularly common in
xerothermic or
arid environments. The
cortex, which forms the outer layer of the thallus, consists of fungal threads (
hyphae) and/or round or irregular cells. The upper part of the cortex is pigmented, while the lower part is colourless and sometimes contains crystal formations visible under
polarized light. These crystals can come from the lichen's own
secondary metabolites or from the it grows on, especially if it is
limestone. The upper surface of
Sarcogyne lichens is typically smooth or slightly wrinkled, and usually ranges in colour from pale to reddish-brown to black-brown, and occasionally rust-coloured. Some species may have a powdery coating (). Cracks often form in the thallus, leading to the lichen's replication through division. The
photosynthetic partner () in these lichens is of the type, forming a continuous or occasionally interrupted under the surface. The lower cortex can be either present or absent. The fruiting bodies (
ascomata) of
Sarcogyne are typically
apothecia, which are disk-shaped structures that can be immersed in the thallus or elevated. These can appear (with a margin that looks like the thallus) or (with a distinct margin). The disk is usually red-brown to black-brown, smooth or wrinkled, sometimes with a powdery coating or pigment build-ups. Inside the apothecia, the consists of numerous thin to stout, often branched filaments (
paraphyses). The
asci, which produce spores, typically contain over 100 spores and are club-shaped. The spores are usually spherical to
ellipsoidal, colourless, and generally small, not exceeding 6
μm in length, except for
Sarcogyne macrocarpa.
Sarcogyne lichens also produce
conidiomata (
pycnidia), which are small, immersed structures that produce asexual spores. The
conidia are small and ellipsoidal to roughly spherical in shape. Chemically,
Sarcogyne species often do not produce
lichen products detectable by thin-layer chromatography , but may rarely contain
gyrophoric or
norstictic acid, which can usually be detected with
spot tests. ==Species==