Slime mould fruiting bodies. Coloured scanning electron micrograph (SEM) of fruiting bodies (sporangia) of a Didymium sp. slime mould. The outer walls (peridia) of the sporangia have burst, revealing spores (orange) and crystals of lime (calcium oxide, white). The lime crystals absorb water vapour from the atmosphere and expand, helping to disperse the spores. Slime moulds are not fungi, but a separate group with complex life cycles. The sporangia are produced when the slime mould encounters unfavourable conditions. Magnification: x40 at 6x6cm size.