Orchil

Roccella presents a fruticose (shrub-like), thallus that is either erect or pendulous (hanging) with sparse dichotomous branching. The main and terminal branches, varying in shape from flattened to rounded (terete), typically measure 2 to 5 mm (up to 10 mm) in thickness and 5 to 15 cm in length. These branches has colours ranging from creamy white-greyish to greyish-brown and have surfaces that are either smooth or wrinkled, with some being sparsely pruinose (powdery) or lacking pruina (epruinose). Soredia, reproductive propagules for asexual reproduction, are present in many species within the genus. The cortex of Roccella lichens is made of hyphae that are arranged in an anticlinal manner and are about 40 to 70 μm thick. The medulla (the inner layer) is loosely structured above, having a byssoid (fibrous) or chalky texture, and below it becomes plectenchymatous (tightly packed cells) near the basal plate (holdfast) area, often showing a (yellowish) brown colouration. These lichens primarily associate with the photobiont Trentepohlia, with no secondary photobiont present. They attach to surfaces using holdfasts, including a hypomedulla which usually appears brown to dark brown, sometimes with a yellowish tinge. The ascomata (spore-producing structures) of Roccella are in the form of apothecia, lateral, and circular in outline. …