MONOADELPHOUS: All the stamens of a flower are united .filament fused anther are free Ex Hibiscus
DIADELPHOUS: Stamens are in two bundles by fusion of filaments anther are free . Ex Pea
POLYADELPHOUS: Filament fused form more than two groups.Ex. Citrus
SYNGENESIOUS: Anther unite to form a cylinder around style filament are free.
SYNANDROUS: Both anther and filament fuse throughout their whole length . Ex Cucurbita
POLYANDROUS: Stamens are indefinite and free. Ex Ranunculus