What are Molds?

Molds are a subdivision of fungi which represent a very diverse group of life-forms on earth.  They are a natural part of our environment in virtually all areas of the planet.

For years fungi were categorized as plants, but scientific studies revealed properties that notably distinguish fungi from plants and therefore, these organisms were given their own kingdom in the classifications of life...Kingdom Fungi.

Mother Nature's Recycling Center
The primary purpose of fungi is to break-down organic matter and unshackle nutrients.  Together with bacteria, fungi decompose the majority of dead organic matter on our planet.

Kingdom Fungi
Classifications within Kingdom Fungi get very complex and are beyond the scope this general overview.  In lay terms, organisms are grouped based on their familiar descriptions including molds, yeasts, mildew, rusts, smuts, mushrooms, and puffballs.  

In our simplified view:

• Molds are microscopic multicellular organisms that grow as long, tangled strands and form visible colonies.  Reproduction is primarily a function of spore development and dispersal.

• Yeasts are microscopic unicellular organisms whose colonies appear as groups of orbs...like berries.

• Mildew, rusts, and smuts are primarily associated with plants.

• Mushrooms, toadstools and puffballs are visible, fleshy organisms.

It's Only Mildew...

Many people refer to 'mildew' as the commonly occurring fungi that grow on damp clothing or bath tiles as if it is a more friendly organism.

In reality, such growth is typically a filamentous mold of the types likely found on water-damaged building materials.

On this site, the term 'mildew' is used to describe types of fungi more commonly associated with living plants (i.e. powdery mildew).

Saprobes, Parasites and Pathogens
Most fungi feed on dead organic matter (a saprobe), however, some types are parasitic and feed on living things.  Pathogenic (disease causing) fungi are known to cause adverse health in animals and humans.

A Note on Conventions
Molds are named and catalogued in accordance with the scientific classifications of Taxonomy.  Mold names are usually presented as a genus (i.e. Aspergillus) or in the genus-species format (i.e. Aspergillus flavus).  Unfortunately, many Latin names are used which makes for some tongue twisters.

The genus is typically capitalized and the species is written lower case.  The convention of Aspergillus spp. is used to indicate all species of the Aspergillus genera and Aspergillus sp. is used to indicate one species.  The abbreviated convention of A. flavus represents the full genus-species name of Aspergillus flavus.  Note that when written, mold names are typically italicized or underlined.   

Taxonomic Ranking

• Kingdom

• Phylum (Division)

• Class

• Order

• Family

• Genus

• Species

Mycology
Mycology is the study of fungi and some consider a mycologist to be part biologist, chemist, naturalist, cryptologist, and wizard.

Note that the study of fungi is far from complete.  Mycologists have described an estimated 80,000 species of fungi and many believe that this is only a fraction of what remains to be discovered.  Estimates of 1.5 million species and variants have been suggested.

To understand the complexities facing these professionals, jot down the names of the first 80,000 people you know and describe their behavior in various settings.  (Yes, there is probably even a fungus that acts like that relative no one speaks about.)

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