Watch out: if you ever find yourself writing homogenous, you probably mean homogeneous.
According to the New Oxford American Dictionary:
Homogeneous: “of the same kind, alike … consisting of parts all of the same kind.”
Homogenous: “an old fashioned term for homologous,” which means “having the same relation, relative position, or structure.”
This is one of those distinctions you never notice until you become an editor.