In botany terms the difference between flower and scyphus

is that flower is a reproductive structure in angiosperms (flowering plants), often conspicuously colourful and typically including sepals, petals, and either or both stamens and/or a pistil while scyphus is the cup of a narcissus, or a similar appendage to the corolla in other flowers.

As nouns the difference between flower and scyphus

is that flower is a colorful, conspicuous structure associated with angiosperms, frequently scented and attracting various insects, and which may or may not be used for sexual reproduction while scyphus is a kind of large drinking cup used in Ancient Greece and Ancient Rome, especially by poor people.

As a verb flower

is to put forth blooms.