This section is from the book "British Wild Flowers - In Their Natural Haunts Vol5-6", by A. R. Horwood. Also available from Amazon: A British Wild Flowers In Their Natural Haunts.
As has been noted elsewhere, a damp habitat is not, as a whole, conducive to attack by fungi. There are some few paludal types of fungi, but they are not of frequent occurrence; and though moulds attack the tissues of plants in moist situations, when they have been already subjected to adverse conditions, plants in a healthy state are not usually infected. The fungi that infest bog and marsh plants belong chiefly to the smaller parasitic types, mainly rusts, smuts, mildews, and moulds.