Gasteromycetes (Puff balls)

The Gasteromycetes represent a number of orders that are not closely related. The common name "puffballs", refers to the basidiospores being "puffed" from the basidiocarp, in some species.  Unlike the Agaricales and Aphyllophorales, the puff balls do not forcibly eject their basidiospores. This has led the puffballs to evolve several interesting means of basidiospore dispersal (Figs. 15-18).

The terminology having to do with basidiocarp structure  also differ. A hymenium is not formed in this group of fungi. Basidia and basidiospores are formed throughout the fertile area of the basidiocarp called the gleba. The part of the basidiocarp that encloses the gleba is referred to as the peridium. These terms will be referred to as we look at the examples below.

Figure 15. Lycoperdon perlatum is a species belonging to the order  Lycoperdales. The peridia of the basidiocarps are the globose sacks that you see on the left. They enclose the gleba, which is a powdery mass of basidiospores at maturity. Basidiospores are released 
through the ostiole when raindrops or small mammals impact the pliable peridium and causes the basidiospores to "puff" out. Click on the picture on the left and see dispersal of basidiospores following an object depressing the peridium of the basidiocarp.
Figure 16. Geastrum tripex is also a member of the Lycoperdales and disperses its basidiospore by the same mechanism as the above example. This species is commonly called an earth-star because of the stellate dehiscence of the outer, leathery peridium. The inner 
peridium, which encloses the basidiospores, is soft and pliable.
Figure 17. Aseroe rubra is a member of the order Phallales. This order is commonly called the stink horns because of the offensive odor that they emit when the basidiospores are mature. The gleba can be seen to your left on forming a slimy, dark, reddish-brown, 
circular area at the center of the basidiocarp. The offensive odor of the gleba, as well as its coloration, attracts flies, which then disperses the spores. The peridium, which enclosed the entire basidiocarp is not present in this photo. Click on the picture on the left and see an example of fly dispersal in this species.
Figure 18. Cyathus sp. is a member of the order Nidulariales. This order is commonly called the bird's nest fungi because of their resemblance to a bird's nest with eggs, within. The "nest" is the peridium of the basidiocarp and the "eggs" are called peridioles, 
which contain the basidiospores. It is the peridiole that is the dispersal unit. When raindrops fall into the center of the peridium, the impact causes the peridioles to be splashed out. Although this only disperses the peridioles a short distance, over a long period of time, this species can cover a significantly, large area.

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