The familiar mushrooms found on pizzas and in the lawn are part of a group of fungi called club fungi, or basidiomycetes. The phylum Basidiomycota consists of 16,000 different species of fungi, including the shelf or bracket fungi found on dead trees and the less well known puffballs, bird’s nest fungi, and stinkhorns. All of these are fruiting bodies, a reproductive structure where spores are produced and released, and are called basidiocarps. They contain the basidia (from the Greek basis, meaning pedestal) which is the familiar club-shaped structure that produce basidiospores.
Club fungi do reproduce asexually occasionally; however, they usually reproduce sexually. The monokaryotic hyphae of two different mating types meet to fuse into a dikaryotic mycelium, which can continue its existence for hundreds of years. In mushrooms, the dikaryotic mycelium radiates out and produces basidiocarps in an ever larger “fairy ring.” In puffballs, spores are produced in the parchment-like membranes and released through pores or when the membrane breaks down. In bird’s nest fungi, falling raindrops provide the force necessary to send the nest’s basidiospore-containing “eggs” flying through the air to land on some other vegetation so it can be eaten by an animal. They pass through the digestive tracks of animals unharmed and are distributed over a large area. Stinkhorns resemble a mushroom with a spongy stalk and a slimy, compact cap. They give off an incredibly horrible odor that attracts flies. When the flies land to feed on a sweet jelly produced by the stinkhorn, they pick up the spores that they later distribute.
Types of Club Fungi
Club fungi come in several types, including mushrooms, puffballs, bird’s nest fungi, and stinkhorns. Two other types of club fungi that are of great economic importance are smuts and rusts. Smuts and rusts are club fungi that parasitize cereal crops and cause huge crop loss every year. They don’t form basidiocarps, and their small numerous spores resemble soot.
Some smuts enter the seeds and live in the plant, becoming visible only near maturity. Others affect the plant externally. The corn smut mycelium grows between the kernels of corn and secretes substances that cause the development of tumors on the ears of the corn. Rusts usually have a more complicated life cycle because they usually require two different plant host species to complete the cycle. For instance, black stem rust of wheat uses barberry bushes as an alternate host, and blister rust of white pine uses currant and gooseberry bushes. Eradicating these alternate hosts in areas where these rusts are a problem usually keeps the rusts in check. Wheat rust is kept in check by producing new resistant strains of wheat continuously to keep up with the adaptable, mutating rust.