Leprose lichen

Leprose

A leprose lichen, which is typically considered to be a form of crustose lichen, is one with a powdery or dust-like appearance. Its undifferentiated thallus is an irregular mix of fungal hyphae and scattered photobiont cells, lacking a cortex or any definable layers. Morphologically, it is the simplest growth form. The cell walls of leprose lichens contain chemical compounds which make them hydrophobic, and thus largely water repellent. However, the lack of a cortex allows them to absorb water directly from humid air. Leprose lichens often grow in damp, shaded places generally untouched by rain. They can be completely covered in soredia – small aggregates of fungal hyphae and photobiont cells which can break off to form new lichen colonies. They have never been found with fruiting bodies. The term "leprose" derives from the Latin leprosus, meaning "scurfy" or "scaly" (from the Greek lepras, meaning "leprosy").