Agaricus, poss. xanthodermus

[alge]

I found a huge troop of these fungus in a local wood, the troop is over 20' diameter and almost unbroken.

The stems have a bright yellow patch at the base, the robust rings are present on most fruit bodies, the caps were yellowing on the underside of the rim & you can see the grey patches on the cap in the mature specimen in the background.

I didn't smell them but i do intend to go back when i can.



Phillips has these as on the red data list but isn't showing on my version for kent so is that region specific?

Any help appreciated as i tend to steer clear of the agaric minefield.

Alex

[Ditiola]

There are at least three species of Agaricus that exhibit a yellow stain at the stem base, but only A.xanthodermus is common. I find it quite a lot especially in parks and gardens in shrub beds under trees etc. When young the caps often have flattish sides like a drumstick.

Peter

[alge]

thanks peter i'll check the younger ones too.

Do you or anyone know if you can get an idea of age of the mycelium by the diameter of the troop ring?I've looked through my limited books but cant find anything.

alex

[Ditiola]

Hi
No I do not knowhow to assess the age by the size of the ring, although I would expect it may be different for different species and probably depends on such factors as:

Vigour of the fungus
Amount of other antagonistic organisms in the soil
Availability of suitable carbon food source
Ease of penetration through the soil
Temperature
Water availability

Perhaps this is something you could study by measuring various rings of different species each year and noting weather conditions etc.

I would think in many cases it is a few inches per year.

Peter

[alge]

That could turn into a lot of study! i lost count at around thirty troops comparable in starting size for it to work, then times that by a reasonable number and I get your point.

Im interested in taking a few diameter measurements and going back next year on the same date to see if it appears to be bigger, it may take repetition over a few years but its something i'm keen to try to do on a few clear troops.

alex