"We don't know what we are going to find, but the heavy rain should bring out some good examples," said Rita Cook, president of the North West Fungi Group.
She and others are spending the week rummaging around grassland and woods for mushrooms and toadstools and taking them back for analysis at Huddersfield University.
"You have to be careful how you dig them up, make sure you get the roots, I smell them and taste them to try to identify them.
"Picking them to eat is generally frowned upon because they are under threat by air pollution. Surveys are being carried out all the time to see how fungi are thriving."
The society is dedicated to the study of fungi and was founded in 1896 at a meeting in Selby, north Yorkshire. Today it enjoys international status.
"Fungi play an important part in clearing the debris in woodlands and countryside. It converts it into food for plants," added Ms Cooke.
"It's all quite fascinating. I think fungi are quite beautiful and some of them have very distinctive smells and tastes."
Superstition and myths surround fungi because one day they're here and the next they're gone," explained Ms Cooke. "Take the yellow brain fungus for example. They look like small blobs of yellow jelly. People used to say they were the first aliens from outer space to land on earth because they were found where it was believed shooting stars fell. I think that's quite charming," added Ms Cooke.
"I could go on talking about fungi all day..."
Cantharellus Cibarius (Chanterelle). The Latin name means "good to eat". Relatively common in this country, and much in demand for its vivid yellow colour and sweet taste.
Calvatia Gigantea (Giant Puffball). Can be mistaken for footballs, and may grow to weigh up to 25kg. Tasty if picked young, sliced and cooked.
Fistulina Hepatica (Beefsteak Fungus). Found growing on the sides of trees. Eat raw or cooked. Has a slightly lemony taste.
Aminata Phalloides (Death Cap). Common in south of England. Amanatin poisoning causes severe stomach upset, and subsequent liver and/or kidney dysfunction.
Cortinarius Speciosissimus. Causes Orellanine syndrome with damage to liver, kidneys and spinal cord. Usually fatal. Found mainly in Scotland.
Aminata Verina (Fool's Mushroom). Quite rare. Reported to have a good taste. Symptoms of Amanatin poisoning felt after eight hours.
Gymnopilus Junonius. Relatively common species of psychoactive fungus which tastes bitter and can cause hallucinations.
Psilocybe semilanceata (Liberty Cup). "Magic mushroom" can be picked and eaten raw without breaking the law, but processing to make the active ingredient psiliocybin more potent could be illegal.