Is this a mushroom or what?

[Wysocki]

I get a strange growth in my lawn that looks like a horse dropped something. It's very firm and if I break it, a bunch of rust colored dust comes out. What is it and how can I prevent it from coming up?

 

[Marck]

Yes, this interesting fungus is Pisolithus arrhizus (or a related species), also known by the amusing common name of Dead Man's Foot. Pisolithus species are known to be ectomycorrhizal. This means they develop mutualistic symbioses with the roots of some trees and shrubs. This symbiosis benefits the tree by increasing uptake of water and nutrients. Be glad you have this beneficial fungus in your soil.

I also have Pisolithus arrhizus in my garden. When I encounter a ripe fruiting body (mushroom) while hose-watering my garden. I will hit it with a stream of water, which creates a colorful cloud of spore dust, like a magician's smoke bomb. It's a fun effect.

 

[Chuck]

When they show up in my vegetable garden every month or so I usually save a couple by putting them in a jar and then when I am going to set out my transplants I dust the roots with the fungal spores. It seems to help the transplants uptake nutrients and moisture for rapid growth. My dad taught me this and his dad taught him. I don't know for sure but it seems that the only time these appear is when there is an abundance of organic matter in the soil so I guess having them is a sign of good soil.

 

[DirtMechanic]

Yes, this interesting fungus is Pisolithus arrhizus (or a related species), also known by the amusing common name of Dead Man's Foot. Pisolithus species are known to be ectomycorrhizal. This means they develop mutualistic symbioses with the roots of some trees and shrubs. This symbiosis benefits the tree by increasing uptake of water and nutrients. Be glad you have this beneficial fungus in your soil.

I also have Pisolithus arrhizus in my garden. When I encounter a ripe fruiting body (mushroom) while hose-watering my garden. I will hit it with a stream of water, which creates a colorful cloud of spore dust, like a magician's smoke bomb. It's a fun effect.

You should elaborate on the outside "ecto" vs the "endo" mycorrhizal functions. How they draw nutrients and moisture to the surface of the roots and why and how and if they get something from the plant in return. It is something worth knowing for gardeners and your spelling is better than mine.

 

[Chuck]

You should elaborate on the outside "ecto" vs the "endo" mycorrhizal functions. How they draw nutrients and moisture to the surface of the roots and why and how and if they get something from the plant in return. It is something worth knowing for gardeners and your spelling is better than mine.

Here is the way I understand your question in layman's terms although your question was not directed to me. The difference between ecto and endo mycorrhizae is that the ecto does not go very deep into the root of the plant while the endo does. They attach themselves to and into the plants roots where they grow and as they grow they extend into the surrounding soil absorbing moisture and nutrients which is then transferred into the plant in a form that the plant can uptake. I know this is a simplified and probably not a 100% accurate explanation but I am sure our doctor of horticulture and botany can give a much better and detailed explanation of your question.

 

[DirtMechanic]

Here is the way I understand your question in layman's terms although your question was not directed to me. The difference between ecto and endo mycorrhizae is that the ecto does not go very deep into the root of the plant while the endo does. They attach themselves to and into the plants roots where they grow and as they grow they extend into the surrounding soil absorbing moisture and nutrients which is then transferred into the plant in a form that the plant can uptake. I know this is a simplified and probably not a 100% accurate explanation but I am sure our doctor of horticulture and botany can give a much better and detailed explanation of your question.

The fact that they want to touch each other was a bit of an aha moment for me when I first read about it. It was during my "Tea" phase as I recall. The idea that a plant would put out sugars to attract certain biodome was pretty wild to me. Or that fungal roots could go so deep past the plant roots. No wonder they shock when you dig them up.

 

[Marck]

Hmm, two other posters kindly stepping back and requesting that I explain topics for which near-countless books and papers have already been written, with countless more yet to come. How kind.

I think I'll just jump over a lot of that and go straight to the take-home: Attention all gardeners: You want your soil to have a diverse array of fungi, bacteria, and other microbes and invertebrates. Most will help your plants grow and many different kinds will allow for alternate strategies as the environment changes and can help prevent an invasion of a single pathogen, A.K.A. disease.
Of course, that is a simplification, It is very complex and variable. Everything does not always work the way you want it to... or rather how you think you want it to.

Any question?

What is the difference between endo and ectomycorrhizae?

Mycorrhizae are categorized by which plants and fungi are involved and how exactly they attach to and interact with each other. For now that is all the explanation you'll get from me. You have the Internet too, use it.

Which kind of mycorrhizae is 'better'?

That totally depends on a huge array of biotic and abiotic variables constantly changing due to time, location, chemistry, climate, and genetics. So many variables that the question really does become pointless. In the end, don't worry about it, you won't get to choose anyway and you'll probably screw it up if you try.

Here are few pretty diagrams that might help explain some of it... or not.

 

[DirtMechanic]

That last image amazed me. I had not had a reason to search how they are grouped because as you say I cannot influence too much. I know just enough to have some sense of the vast numbers involved with phytohormones and I can imagine that myco grouping picture is a doorway to a deep rabbit hole should I look behind it. I think I will download it. Maybe it can be an avatar?

 

[NigelJ]

A recent good book touching on this subject was Merlin Sheldrake's "Entangled Life".
Although quite old now I found this site informative http://mycorrhizas.info/roles.html#intro

 

[Marck]

That last image amazed me. I had not had a reason to search how they are grouped because as you say I cannot influence too much. I know just enough to have some sense of the vast numbers involved with phytohormones and I can imagine that myco grouping picture is a doorway to a deep rabbit hole should I look behind it. I think I will download it. Maybe it can be an avatar?

That root cross-section would make an interesting avatar.