is a specific kind of: fungus.

is a broader term that covers: flax rust, flax rust fungus, Melampsora lini | blister rust, Cronartium ribicola | Puccinia graminis, wheat rust | apple rust, cedar-apple rust, Gymnosporangium juniperi-virginianae.

has as a part: aecium | aeciospore.

is a member of: order Uredinales, Uredinales.