Tylophoron is a genus of
crustose lichens that typically appear as thin, often powdery or slightly felt-like patches spread across their . Although the
thallus (lichen body) does not have a distinct outer skin (), it may be coated with tiny crystals. Around the edges, a brown, radiating network of fungal strands (the ) often forms a noticeable border. The lichen's
photosynthetic partner is from
Trentepohlia, a genus of
green algae. The reproductive structures (
apothecia), when present, sit on the surface and range from short, cylindrical to cone-shaped. Most create a specialised spore mass called a . A ring of lichen tissue (the ) surrounds the apothecia, often thickened at the base and dotted with minute crystals. Beneath this, the —made of dark brown, hardened fungal threads—provides structural support. The
asci (spore-producing sacs) are cylindrical and hold their spores in a single row. As they mature, the asci dissolve, leaving a powdery black mass of spores (the mazaedium). The spores are thick-walled, dark brown, and divided into two cells by a single internal wall (
septum). Another form of reproduction involves —small, rounded or dome-shaped structures that can range in colour from pale creamy yellow to black, appearing singly or in small clusters. These produce chains of spores (
conidia) from terminal cells. The conidia themselves can be colourless or dark brown, generally without internal divisions, and shaped like elongated cylinders or tapered at the ends. From a chemical standpoint,
Tylophoron species can react in various ways with standard chemical
spot tests. The main body (thallus) is K− and may show a red colour change with chlorine (C+ red) or no reaction at all (C−). Some species glow bright yellow under
ultraviolet light (UV+), while others do not (UV−). Common
secondary metabolites in these lichens include
lecanoric acid, and in some cases, 2'-
O-methylperlatoic acid or
lichexanthone. ==Distribution==