This is the simplest fungal laboratory exercise that I know. I recommend it to anyone wanting to show fungi to their class as a first exercise. The students learn that fungi are found throughout the environment, and that they reproduce themselves by spores. These facts were demonstrated by Pier' Antonio Micheli in the late 1600's and early 1700's in Florence, Italy using these same materials. His work was not fully appreciated until the time of Pasteur, over a century later.

• Two medium pumpkins (or melons or squash)
• A big sharp clean knife
• A big strong clean spoon
• A cutting board
• 24 clear plastic pint delicatessen containers with lids
• A new package of flat toothpicks
• Soil, moldy food, rotten fruit, leaf litter, etc.

Culturing fungi from nature. To get some cultures of fungi, use the big sharp knife and cutting board to cut the pumpkin into pieces that will fit in 12 of the deli containers. Scrape the seeds and placenta off with the spoon. Give two containers with pumpkin to each group of four students. Have them put small amounts of things like soil, moldy food from their refrigerator, rotten fruit from home or the store, etc. on each pumpkin. Close the lids and watch to see what comes up. When you see colored colonies on the pumpkin, you probably have fungi that are producing spores (there will also be bacterial colonies, which look like little drops of yogurt and can also be colored) When you have some fungi, you are ready to make some fungal gardens.

Fungus gardens. Make another dozen pumpkin dishes with the other pumpkin and clean utensils. Pieces with several facets or faces (like a gem stone) are the best for this part of the exercise. Have the groups of students use the toothpicks to transfer different types of fungi to the different faces of the pumpkin. Some of the fungi will have grown rapidly over the pumpkin; they will do the same over the new piece, so you might encourage the students to try and avoid them. Alternatively, these fungi are guaranteed to yield results. Cover the new pumpkins and wait. The students should be able to see that the types of fungi transferred from the environmental isolates have made the same type of fungi on the new pieces of pumpkin. This is expected, because fungi have spores for reproduction, a situation analogous to the seeds produced by plants. If you have a microscope, dissecting or compound, have the students examine their fungi at close range.