AY Honors/Fungi/Answer Key

1. Give the name of five classes of fungi and examples of each.

Chytridiomycota

The phylum Chytridiomycota, the chytrids, represents a group of primitive aquatic fungi. They are characterized by having reproductive cells can move themselves by using whip-like tails called flagella. Synchytrium endobioticum is a chytrid fungus that causes the potato wart disease or black Scab.

Zygomycota

The zygomycetes, in phylum Zygomycota, are characterized by the formation of sexual spores called zygospores. The zygospores are not contained within a specialized fruiting body or sac. An example of a zygomycete is the common black bread mold, Rhizopus nigricans.

Glomeromycota

Members of the Glomeromycota are also known as the arbuscular mycorrhizal fungi. Only one species has been observed forming zygospores; all other species only reproduce asexually.

Ascomycota

The ascomycetes are members of the phylum Ascomycota. They are also called the “sac fungi” because their sexual spores (ascospores) are enclosed in tube-like sacs known as asci. Familiar examples of sac fungi include morels, truffles, Baker's yeast, Dead Man's Fingers, cup fungi, and the majority of lichens (loosely termed "ascolichens") such as Cladonia.

Basidiomycota

Basidiomycetes, also known as the “club fungi,” are classified in phylum Basidiomycota. Basidiomycetes include some of the most complex fungi, including mushrooms and puffballs.

2. Identify fifteen common fungi of your locality. Draw or photograph them from live specimens.

The best way to approach this requirement is to go out looking for fungi, and then try to figure out what you have found. This is far more effective than studying your field guide, deciding what you want to look for, and then going out for a look.

To do this, you will need a field guide. The field guide you select should cover the area where you are looking for mushrooms. For example, a field guide to the mushrooms of Australia is not going to help you very much if you're looking for fungi in North America.

Once you have a field guide, take it, plus your camera or sketch pad, and go out looking for fungi. When you find one, try to figure out what it is using your field guide. It is difficult to distinguish the various species of fungi from photographs alone, so you will want to identify it on the spot. Many times the identification of a species will rely on an obscure feature such as the gills on the underside of a mushroom. Chances are, if you attempt to identify the fungus later from a snapshot, you will not have captured one of the critical identifying features, or the feature was not sufficiently in focus. That is why you will want to make an identification when you have direct access to the specimen. If you find yourself looking at an interesting specimen and do not have your field guide with you, by all means, sketch it out and take photos. There is always the chance that you will be able to identify it later. Take special notice of the gills (if there are any), how they attach to the stem, and any "fringes" around the stem.

3. Name three important fungi and tell what their value is.

Saccharomyces cerevisiae

This fungus is used in baker's yeast.

Aspergillus niger

This fungus is used to make citric acid commercially, and it also can be used to make gluconic acid. Both are important food additives.

Penicillium chrysogenum

This is the organism that makes penicillin, from which the majority of the large class of beta-lactam antibiotics are derived. Penicillin and its derivatives have saved countless lives since they were discovered and isolated, starting in the 1940s.

4. Tell the life history of one example of each of the following:

a. Rust

The life histories of rusts often are mind-bogglingly complex, often with the fungus spending part of its life on one kind of plant, then another part on a completely different kind of plant. For example, near my trailer there's an Eastern Redcedar tree, Juniperus virginiana. All winter some brown, bumpy, woody, tumor-like items about the size of golfballs were visible growing on the branches. In early spring the bumps on the thing developed slender, sharp "horns" from which pollen-like dust emerged.

5. Identify five fungus plant diseases.

Fusarium oxysporum

Adventist Youth Honors Answer Book/Nature/Fungi/Fusarium oxysporum

Downy mildew

Adventist Youth Honors Answer Book/Nature/Fungi/Downy mildew

Botrytis (Leaf blight, Neck rot)

Adventist Youth Honors Answer Book/Nature/Fungi/Botryotinia

Alternaria alternata

Adventist Youth Honors Answer Book/Nature/Fungi/Alternaria alternata

Smut

Adventist Youth Honors Answer Book/Nature/Fungi/Smut

Magnaporthe grisea

Adventist Youth Honors Answer Book/Nature/Fungi/Magnaporthe grisea

References

• http://www.caes.state.ct.us/PlantPestHandbookFiles/pphO/pphonio.htm