Poplar Fieldcap? Rare?

[Steve Wurzel]

This is a clumping mushroom found on a mature deciduous stump in Bristol which I revisited after first spotting these in June last year, and to my surprise not only were they there in mid-May but I had obviously missed an earlier bloom which looked about 1-2 weeks old.

Strangely we suspected Agrocybe cylindracea Poplar Fieldcap on another clump I found in Somerset on what was probably a willow stump, so I'm wondering how rare these are in the West Country.

This time I've obtained a young sample and have it sliced and now set for a spore print, which will hopefully help clinch the ID.



The smaller mushroom here is 60mm across the cap whereas the mature sample is closer to 180mm..



Cap 40mm - 180mm. cream when young, cracked cream to brown when mature.
Stem firmly attached to cap, solid and strong, and oval shaped in diameter.
Smell.. mushroom and spinach, grassy.. it's quite strong but hard to describe!!
Ring.
Clumping in small groups of 5-10 (ish), growing on deciduous roots.
Gills cream when young, cigar brown when mature.

Slugs love it!!

If it is Poplar Fieldcap (Southern Poplar Mushroom), is it rare in the UK? should I do anything more if it is? Are there different subspecies? Which is the correct name Agrocybe cylindracea or Agrocybe aegerita


Positive ID required fast..."excellent eating, with a nutty taste".. gotta beat the slugs

[mykonik]

Originally Posted by Steve Wurzel

This is a clumping mushroom found on a mature deciduous stump in Bristol which I revisited after first spotting these in June last year, and to my surprise not only were they there in mid-May but I had obviously missed an earlier bloom which looked about 1-2 weeks old.

Strangely we suspected Agrocybe cylindracea Poplar Fieldcap on another clump I found in Somerset on what was probably a willow stump, so I'm wondering how rare these are in the West Country.

This time I've obtained a young sample and have it sliced and now set for a spore print, which will hopefully help clinch the ID.



The smaller mushroom here is 60mm across the cap whereas the mature sample is closer to 180mm..



Cap 40mm - 180mm. cream when young, cracked cream to brown when mature.
Stem firmly attached to cap, solid and strong, and oval shaped in diameter.
Smell.. mushroom and spinach, grassy.. it's quite strong but hard to describe!!
Ring.
Clumping in small groups of 5-10 (ish), growing on deciduous roots.
Gills cream when young, cigar brown when mature.

Slugs love it!!

If it is Poplar Fieldcap (Southern Poplar Mushroom), is it rare in the UK? should I do anything more if it is? Are there different subspecies? Which is the correct name Agrocybe cylindracea or Agrocybe aegerita


Positive ID required fast..."excellent eating, with a nutty taste".. gotta beat the slugs

Hi Steve - yes, Agrocybe cylindracea !

Both names are 'correct' but the cylindracea epithet was given to this species prior (1815) to the aegerita epithet (1824) thus has nomenclatural priority.

Nick

[fairplay]

Not a positive ID without microscopic details I'm afraid, but I am confident as I can be this is Agrocybe cylindracea (correct name)

Do try to find out if the stump is a Willow or Popular (there may be suckers/regrowth showing) which would clinch it.

As with any new species of edible fungi, only try a few first (on the missus) but it 's nearest look a like A. praecox is also edible, so you don't have too much to worry about.

Naturally, an ID by photo alone is risky, so it is YOUR decision if you decide to eat them.

Neil.

[fairplay]

Sorry Nick, I started my post just before you had sent yours and didn't know you had responded. At least we agree.

Neil.

[mykonik]

Originally Posted by fairplay

Sorry Nick, I started my post just before you had sent yours and didn't know you had responded. At least we agree.


Neil.

Some very valid points though Neil - but in this case the diagnosis is fairly clear cut and you wouldn't necessarily have to do the microscopy to diagnosis this taxon - it isn't part of a 'critical' group of species and the macroscopic features and the general 'jizz' of the basidiomes alone will be enough to make a positive diagnosis !

I might also point out that although preferring Populus sp. [most of the herbarium specimens say P. nigra as the host], the host is not diagnostic since A. cylindracea is pluriverous in it's choice of hosts and is found on numerous other species of trees, eg. the second most commonly recorded host is sycamore (Acer pseudoplatanus)

Nick

[Steve Wurzel]

Originally Posted by fairplay

Do try to find out if the stump is a Willow or Popular (there may be suckers/regrowth showing) which would clinch it.

Definately not Willow, the remaining stump was about 1m diameter and round, and the exposed roots are substantial, there were Elm growing there in the 70's but they were ravaged by Dutch Elm disease, so possibly not Elm either. The stump is overgrown with brambles, where the mower can't get them!! So I can't say anymore than mature deciduous at this point.

It couldn't have been particularly Popular.. they cut it down


The spore print is ready and it's a rusty brown or light cigar brown..



FYI black insulation tape seems to work great for showing up spores... useful if you suspect a white spore print may be produced.

Gills adnate or slightly decurrent, cream at first then tobacco brown due to the spores. Spore print tobacco brown.

Rogers Mushrooms - Agrocybe cylindracea Mushroom

All of which concurs with the features of Agrocybe cylindracea


Agrocybe praecox appears to be differentiated from Agrocybe cylindracea by only a few features that I can see.. it doesn't grow in dense clumps, it doesn't seem to grow as large as the Poplar Fieldcap, smell mealy v "old wine casks", (the sample I took has a sweet high note.. reminiscent of sherry.. grassy with a sweet high note, a hint of aniseed perhaps.) and Agrocybe cylindracea does seem to require a host "stump" or root system as a substrate.

Even the microscopy might not help as both sets of spores are ovoid and virtually the same size!!

Agrocybe cylindracea
Spores ovoid-ellipsoid, 8.5–10.5 x 5–6µ.

Agrocybe praecox
Spores ovoid-ellipsoid, 9–10 x 5–5.5µ.

I'd say that was a positive ID for Agrocybe cylindracea unless anybody can throw in another contender?


Any comments on the rarity of this funghi.. is it rare?

[mykonik]

Hi Steve - Agrocybe cylindracea isn't rare, rather 'occasional' and more frequent in some years than others !

Mostly collected / recorded in southern or south-western England with few records elsewhere in Britain.

Nick

[CloudedYellow]

Originally Posted by mykonik

Hi Steve - Agrocybe cylindracea isn't rare, rather 'occasional' and more frequent in some years than others !

Mostly collected / recorded in southern or south-western England with few records elsewhere in Britain.

Nick

This cluster were found last week in Notts.

Can't have been many slugs about as I managed to get these over the course of the week. I have posted the first image before but not the subsequent ones:







Richard

[Steve Wurzel]

Thanks for clearing that up Nick.

I had a nibble on a well cooked half cap earlier, and I'm still alive

Quite a nice taste, a nutty twang.

[Steve Wurzel]

Oops posted together there CY!!

The ring is much larger on your sample Richard, it looks like there are no slugs in Notts