Sphagnum rubellum

These are leaves of Sphagnum, a moss that is found in bogs. Actually, Sphagnum creates bogs (see the introduction for more information). Sphagnum leaves contain two types of cells: hyaline cells and chlorophyllose cells. The hyaline cells are the large worm-like cells with holes (pores) in them. They are specialised for water retention. The pores allow water to enter easily, and the leaf acts like a giant sponge. The chlorophyllose cells are much smaller, sandwiched between the hyaline cells, and cannot be seen in this picture. They are the photosynthetic cells in the leaf.