Biatoropsis is a genus of fungi that parasitises lichens (making it lichenicolous). The fungus produces reproductive structures called basidiomata that vary in both shape and colour, with a waxy-gelatinous texture similar to jelly.[5]
At a microscopic level, the internal tissue (context) consists of thread-like cells called hyphae that lack specialised connecting structures known as clamps. The fungus penetrates its host using specialised feeding structures called haustoria, which have a distinctive twisted or convoluted form characteristic of the Tremellales order of fungi. The reproductive surface (hymenium) contains numerous immature spore-producing cells called probasidia. These initially develop in a club-shaped form and may or may not have a clamp at their base. Unlike some related fungi, Biatoropsis lacks specialised sterile cells called hyphidia and cystidia in its hymenium.[5]
When fully mature, the spore-producing cells (basidia) are club-shaped to almost cylindrical and divided by cross-walls (septa). These cells develop extensions called epibasidia that are roughly cylindrical in shape. The spores (basidiospores) they produce are nearly spherical to elliptical in shape and have a distinctive side projection called an apiculus. When these spores germinate, they do so by producing a tube-like growth.[5]
The fungus can also reproduce asexually in several ways. It commonly produces chains of spores called catenulate conidia. In one rare observation, crescent-shaped (lunate) conidia were documented. In one species of Biatoropsis, the basidia themselves can function as cells that produce asexual spores – these spores are colourless and lack internal divisions.[5]
All species in the genus parasitise species of the fruticose lichen genera Usnea and Protousnea, causing gall-like symptoms in infected species.[5]
