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 core pollen grains and stratigraphy of the core so researchers frequently select locations where the sediments are under anaerobic conditions. The cores are then subjected to pollen analysis by palynologists who are able to infer the proportions of major plant types from the concentrations of different pollen types found in the cores. There are a number of tools used for coring, often with specialized uses: Pollen core A pollen core is a core sample of a medium containing a stratigraphic sequence of pollen. Analysis of the type and frequency of the pollen in each layer is used to study changes in