Hands and Knees "Fungi"
Slime mold is often called "hands and knees fungi" because it helps to be on your hands and knees to see them well. There are over 700 named varieties of these fungus-like organisms. They vary drastically in their size, shape and color and are found during periods of very wet weather.
What is a Slime Mold?
Slime molds are not true fungi but primitive fungal-like organisms currently classified with protists. More than 700 different species of slime mold exist. Those found on lawns or flowerbeds have a two-part life cycle. During warm, moist weather the slime mold lives as a shapeless, growing blob called a plasmodium. The plasmodium may be gray, cream, colorless, bright yellow or orange. A plasmodium can slowly creep across the ground, moving like an amoeba and consuming bacteria, fungi and organic debris as it moves. Beds of shredded, decaying wood mulch are prime real estate for slime molds because mulch is especially full of tasty fungi and organic debris. Those that live on turf feast on the fungi and bacteria that live in the thatch. When the environment dries out, the plasmodium transforms its shapeless body into many small, often stalked, fruiting bodies that are full of dust-like spores. Sometimes, a plasmodium moves itself to a dry spot to accomplish this transformation. The dry, sporulating slime mold often looks hard and crusty. The tiny spores can remain dormant in the soil for years, waiting for another period of moist weather, when they germinate and each release a small, motile cell. Two motile cells fuse together and grow to become a new plasmodium, starting the cycle anew.
(Thanks to Iowa State University Extension for the above definition.)