Guide to Myxomycetes

Myxomycetes are fungus-like organisms that reproduce using spores. Separate from fungi, myxomycetes are macroscopic slime molds that feed on dead plant and animal material. Common in places like lawns and forest floors, they are also found in tropical areas, fruits, and tree canopies. Anywhere there is decaying biological material in adequate quantity, there will most likely be myxomycetes.

Plasmodium is a type of myxomycete and it is the agent that causes malaria in humans. Malaria kills as many as 1 to 2 million people per year so it’s deadly to the human body. There are four different types of plasmodium. The most common type is the phaneroplasmodium, which has a fan-shaped network of veins that actually contain protoplasm. Then, there’s aphanoplasmodium, which has very thin veins and no slime sheathe. Protoplasmodium is the third type and it has no veins. These are always microscopic with a fruiting body. The final type of myxomycete actually has characteristics of both aphanoplasmodia and phaneroplasmodia.

These four types of plasmodium are called “fruiting bodies.” The most common type is the sporangium, which is a spore container that is either stalked or sessile, coming in a variety of colors and shapes. Then you have aethalium bodies, which possess a sessile structure and masses of fused sporangia. These types are generally larger than most other types, in some cases several centimeters.

There is also pseudoaethalium, sometimes known as false aethalium, which is mostly composed of sporangia that is closely grouped together. Finally, there is plasmodiocrap, which is sessile, having the form of the plasmodial veins from which they come. Fruiting bodies have unique structures as well. There are six body parts. There’s the hypothallus, the base of the fruiting body. It can be bright, dull, thin, delicate, or coarse. This connects to the second part, the stalk. The stalk is extremely important to identifying types as they vary greatly in color and texture. The columella is an extension of the stalk into the spore mass. A pseudocolumella is a columella that doesn’t actually attach to the stalk as “pseudo” means false.

The peridium is a covering that encases the actual spore mass. Sometimes it’s present in a mature fruiting body, but sometimes it isn’t. Its presence or lack thereof is important in identifying types. The capillitium is composed of thread-like elements inside the actual spore mass. Sometimes it’s part of a connected network and sometimes it’s composed of free elements known as elaters.

A pseudocapillitium is present only in some species and varies greatly in size, shape and appearance. Sometimes they appear to be bristles, sometimes perforated places, and sometimes as simple threads. Then there are the actual spores, the heart of everything. They can range in size from 5 to 15 micrometers. Almost all of them are round and most of them are ornamented in some way. In fact, entirely smooth spores may not even exist. Spores can be dark-colored or light-colored, spiny, warted, and even finely warted. They come in different shapes and sizes. Spores vary so greatly that some of them can only be identified by the outer casing.

Slime molds are more familiar. They have a purpose in this world, even though many people see them as something that can be harmful. Slime molds are part of the world’s natural biological processes and far more complicated than most assume.

For additional information, check the following sites:

Introduction: An article that offers an overview of basic facts about myxomycetes and their characteristics.

DiscoverLife: Provides images of different types of myxomycetes.

Characteristics: Outlines the different characteristics of myxomycetes depending on type.

The Slime Molds: Breaks down different aspects of slime molds.

Myxomycetes: Overlooked Native Plants: An article that discusses the importance of myxomycetes in an ecosystem.

Myxomycetes: Provides various facts including where myxomycetes grow, where they can be found, how they can be used, and more.

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