Pollinium, or plural pollinia, is a coherent mass of pollen grains.
They are the product of only one anther, but are transferred, during pollination, as a single unit. This is regularly seen in various plants, such as orchids and many species of milkweeds (Asclepiadoideae).
Most orchids have waxy pollinia. These are connected to one or two elongate stipes, which in turn are attached to the sticky viscidium.
Some orchid genera have mealy pollinia. These are tapering into a caudicle (stalk), attached to the viscidium. They extend into the middle section of the column.
The combination of pollinia, caudicles, stipes and viscidium form the pollinarium.
