(1832) Gymnosporangium clavariiforme (tongues of fire)[2] is a species of rust fungus which alternately infects Juniperus and hawthorns.

[3] In junipers, the primary hosts, G. clavariiforme produces a set of orange tentacle-like spore tubes called telial horns.

[4] The spores are released and travel on the wind until they infect a hawthorn tree.

On the secondary hosts, the fungus produces yellowish depressions on the leaves.

It also infects the fruit, which grows whitish tubes like a Medusa head.