Mucilago crustacea is an amoeboid fungus or myxomycete, one of the easiest to realize because the noticeable size and white colour of its fruiting body that stands out among the leaf litter. It is common anywhere throughout the year in wet weather. It forms elliptical fruiting bodies in etalium -a mass of compressed sporangia, impossible to separate- up to 10×5 cm in size, holding a few centimetres above the ground between grasses or enveloping a fallen twig. It has a rough white or yellowish crust, made up of tiny, rounded rods as a handful of boiled rice. If scratched, the inside is black because the spores.
Mucilago crustacea is found in forests. In its crawling plasmodium phase, Mucilago crustacea is very inconspicuous while feeding on soil microorganisms. However, it stands out when it fructifies.
Fuligo cinerea is a similar to Mucilago crustacea species of myxomycete. It is frequent as well; thus, both species are often confused. Fuligo cinerea is found mainly on grasses in meadows and orchards, it is white or greyish white, the shape is a pulvini that do not usually rise from the ground and its surface looks like a sponge.
[photos Jordi Badia (1st) and Just Serra (2nd)]