a form of ... a mode, type or essence of something. Examples: A form of flattery, (a type of flattery) a form of affection, (like a kiss for example, an action that shoes affection.)
a kind of, something similar or nearly like something else. Examples: a kind of athlete (like an athlete but maybe not the typical kind) a kind of vehicle, (a ATV for example) a kind of apple ( say a fuji apple, the type of apple)