Gymnosporangium

The name means "naked spore-bearer of the eastern juniper tree." known to foresters and apple farmers as Cedar-Apple Rust, is not the kind of fungus that usually crosses the radar screens of mushroom hunters. It is a "rust," but unlike many rusts it creates a large and, well, freaky-looking fruitbody during part of its life cycle. Eastern red cedar, Rocky Mountain juniper, as well as a few Chinese, common and prostrate junipers. Hawthorn rust (G. globosum) commonly infects the same hosts listed for cedar-apple rust.

Common on Cedar Trees.