Septobasidium fruit bodies appear on woody plants, generally as flat growths over branches and these growths range from a square centimetre or so to many square centimetres in area. The fruit bodies are velvety in appearance and generally are some shade of brown (from very pale grey brown to deep chestnut brown to blackish brown, but often with a pale margin). In larger coverings there may be cracks or gaps in these flat growths (as you see at https://www.anbg.gov.au/fungi/images-captions/septobasidium-sp-0202.html).
At first glance it is natural to suppose that these fungi are parasitic on the plants on which they appear and, while they do rely on their supporting plants for nutrients, the fungi gain those nutrients indirectly since species of Septobasidium are parasitic on scale insects (without killing them), which in turn are directly parasitic on plants. Some fungal hyphae penetrate scale insects and extract nutrients while others grow over scale insect colonies to form that brown covering. There is a brief explanation on this page: https://www.anbg.gov.au/fungi/ecology-invertebrates.html
If you wish to find out more you should try to find a copy of The Genus Septobasidium by J.N. Couch (University of North Carolina Press, 1938). This magnificent monograph has numerous drawings and photographs and presents a great deal of information about the genus Septobasidium.