Silver fir pollen grain. Coloured scanning electron micrograph (SEM) of a pollen grain from the silver fir tree (Abies sp. ). This is a wind- borne pollen grain, and it has two rounded wings" (upper frame) which enable it to stay in the air. Pollen grains, which carry the male reproductive cells, are released in vast numbers in late spring, and some inevitably land on the female parts of the tree. The silver fir is a common evergreen tree in the mountainous areas of central and eastern Europe. The wood is used in the manufacture of paper, and the leaves of this tree are distilled to produce turpentine. Magnification: x650 at 6x7cm size. x1000 at 4x5""