Why are most grass flowers small and not brightly coloured?

Grass flowers are small and lack bright colors because they are adapted for wind-pollination rather than animal-assisted pollination.12

Unlike plants that rely on insects or birds for reproduction, grasses do not need to produce nectar, strong fragrances, or showy petals to attract pollinators. Instead, they have evolved to be highly efficient at releasing and capturing pollen through air currents. Their flowers are simplified and inconspicuous, often featuring long, feathery stigmas that are well-suited for catching airborne pollen, and anthers that hang loosely or burst open to scatter pollen widely in the breeze. This evolutionary strategy allows grasses to thrive in diverse environments by utilizing the wind as a reliable, albeit less precise, agent of dispersal.123