Pollinia (sing. pollinium): Hardened, cohesive masses of pollen grains, characteristic of orchids.*
When a pollinator visits an orchid, it receives a discrete package of pollen rather than a dusting. The orchid has a sticky structure called a viscidium that actually glues the pollen packages right onto the pollinator. In the photo, my pencil takes the place of the pollinating insect. Once contact with the sticky viscidium is made, the pollinia come away from the flower and travel with the bee to the next orchid. The yellow pollinia themselves can be seen in the last frame.
Many plants in the milkweed family also use pollinia for pollination.
*Leroy-Terquem, G. & Parisot, J. (1993). Orchids: Care and Cultivation. London: Cassell Publishers Ltd.