Images Dated 10th October 2000

Hazel pollen grains

Hazel pollen grains. Coloured scanning electron micrograph (SEM) of pollen grains from the Hazel tree, Corylus avellana. These microspores are shed from male catkins (hanging pollen-bearing structures) on the Hazel tree, released into the air and carried by wind to pollinate the female flowers. Pollen grain shape, size and surface sculpturing varies greatly between species, and may be used by botanists to identify plants from pollen grains. Large quantities of Hazel pollen occur as a fine yellow mist at springtime in parts of Europe, and may contribute to attacks of hay fever (allergic rhinitis). Magnification: x1, 730 at 5x7cm size

© POWER AND SYRED/SCIENCE PHOTO LIBRARY

Lava flow and vent

Lava flow. Night time view of lava flowing from a small vent on Etna. This vent is a hornito, a relatively small outlet which is normally only throws out lava bombs. On occasion, the changing internal structure of the volcano may mean that a hornito becomes the easiest route for lava to reach the surface, and becomes the site of an effusive eruption. Etna is the largest active volcano in Europe. Although internal pressure is normally released by gentle Strombolian activity, Etna also has periodic episodes of intense lava production. Photographed on 1 November 1999

© DR JUERG ALEAN/SCIENCE PHOTO LIBRARY