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
Corn silk Corn silk is part stigma and part style, providing a female flower surface to which pollen grains can adhere and defining the lengthy path through which the pollen must transmit its genetic material. The stigma is the very tip of the corn silk, which has a larger number of hairs to help pollen to adhere to it. Kernel formation in the cob requires pollination of the external corn silk by wind or insects. Usually several grains of pollen adhere, but only one will successfully participate in fertilization of the ovule to form a corn kernel. For the pollen grain, the