Globosphaeria jamesii

Globosphaeria jamesii produces small, dark brown to black, nearly spherical fruiting bodies (perithecia) that grow on the surface of its host lichen. These structures are 0.25–0.3 mm in diameter and have a small opening (ostiole) at the top. The outer wall of the fruiting body is made up of a network of branching filaments and angular cells that give it a distinctive texture. Inside the fruiting bodies are cylindrical spore sacs (asci) that measure 80–90 micrometres (μm) long and 8–11 μm wide. Each ascus contains eight spores arranged in a single row. These spores are spherical (globose), and colourless (hyaline), with smooth, thick walls up to 2 μm thick. They measure 8–10 μm in diameter and each has a single germination pore that allows it to grow when conditions are favourable.

Globosphaeria jamesii was first collected in Waratah, Tasmania, in February 1907, where it was found growing on the squamules (scale-like structures) of the lichen Normandina pulchella. However, the fungus itself wasn't identified and described as a new species until 1990, when Hawksworth examined the historical specimen. The type specimen was very limited in material, containing only two fruiting bodies, one of which had to be sacrificed for the scientific description. The relationship between G. jamesii and its host lichen appears to be either commensalistic (where one organism benefits while the other is unaffected) or possibly mutualistic (where both organisms benefit), as the fungus's pale brown filaments surround algal cells within the host lichen without causing any visible damage or discolouration. After its description in 1990, the species remained known only from its original collection in Tasmania until 1998, when it was discovered for the first time in North America. This new specimen, which contained multiple fruiting bodies, was found near Sappho, Washington, USA, at an elevation of 180 m (590 ft) in an area northeast of Beaver Lake. This discovery not only expanded the known geographic range of the species but also provided additional material for study. Despite these two known locations, G. …