Pollen cell. In flowering plants the vegetative tube cell produces the pollen tube, and the generative cell divides to form the two sperm cells. Pollen is produced in the microsporangia in the male cone of a conifer or other gymnosperm or in the anthers of an angiosperm flower. Pollen grains come in a wide variety of shapes, sizes, and surface markings characteristic of the species (see electron micrograph, right). Pollen grains of pines, firs, and spruces are winged. The smallest pollen grain, that of the forget-me-not ("Myosotis" spp.), is around 6 µm (0.006 mm) in diameter. Wind-borne pollen grains can be
Pollen beetle Pollen beetle Pollen beetle is an informal term for any species of beetle associated intimately with suitably pollen-rich species of flowers. Typically such a beetle is adapted to the pollen as a major part of its diet. Species in at least sixteen families of the order Coleoptera could be counted as pollen beetles, and "pollen beetle" also is a common name for some such species. Many insects of small to modest size benefit from feeding on pollen of suitable plants; pollen tends to be rich in protein, plentiful in season and easily available. Many plants, such as some members of