Quercus sp. are monoecious i.e. male flowers, "staminate" (with funcional stamens) and female flowers "carpellate" (or "pistillate") (having only functional carpels) are found on the same plant. The male flowers used in several recipes are in the form of catkins. The fruit of Quercus sp. is a nut ( acorn or oak nut) in a cup-like structure or cupule with one seed (rarely two or three) /acorn.
Quercus coccifera, acorns, leaves, batk etc. contain tannic acid and have a high tannin content which in excess can irritate the digestive lining. Foliage can be poisonous. Acorns should be leached of bitter tannins & roasted before consumption. Contraindicated in kidney & liver conditions, fever, infectious states, using bark in cardio-insufficiency states & externally (e.g. baths), when skin is damaged especially eczma.