Asterionella ( Gr. asterion, a kind of spider) sp. Diatom colony. Asterionella diatom cells are elongate and joined at the ends by mucilage pads to form star-shaped colonies. The labiate, yellow-brownish chloroplast is distributed over the whole cell length. Culture material of the Culture Collection of Algae at the University of Cologne. Microscopic contrast technique : Differential interference contrast. Magnification 580x when printed 10 centimetres wide.