staminodes

Staminodes are sterile or nonfunctional stamens, modified structures derived from stamens that do not produce viable pollen. They may be reduced to small ridges or become entirely petaloid, taking on a shape reminiscent of petals, and in many flowers they are visible as conspicuous, often colorful structures that contribute to the flower's appearance.

Staminodes can arise from stamens with reduced anthers or from the filament and anther tissue becoming modified. They vary greatly, from scale-like appendages to conspicuous petal-like structures, and in some groups participate in mimicking petals to attract pollinators.

The primary function of staminodes is not pollen production; instead they may contribute to pollination biology by enhancing floral display, guiding pollinators to the fertile reproductive parts, forming nectaries or nectary guides, or protecting the developing reproductive organs.

Staminodes occur in a range of angiosperm lineages and are particularly well known in orchids, where sterile stamens can be highly specialized and form part of the flower's pollination apparatus. Other plant groups may also show staminodes, often as part of the floral structure that shapes the overall appearance. The presence, absence, and form of staminodes can be diagnostic for certain taxa and may reflect evolutionary changes in flower morphology.