This time of year, early June both the female flower head and male pollen-head of the cattail are emerging from their sheaths in the stalk of the plant. Both parts are edible at this stage.
Just release them from the stalk and their papery sheath, sautee, blanch, or steam in butter, garlic, salt or whatever spice you like and eat like corn-on-the-cob. Has an earthy, slight corn taste to it. Makes a nice appetizer.