In botany|lang=en terms the difference between flower and rhizanthous

is that flower is (botany) 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 rhizanthous is (botany) producing flowers from a rootstock, or apparently from a root.

As a noun 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 or flower can be something that flows, such as a river.

As a verb flower

is to put forth blooms.

As an adjective rhizanthous is

(botany) producing flowers from a rootstock, or apparently from a root.