Amanita

SheffieldLass · #1 (**permalink**) 13-10-2009, 08:57 PM

But which one? (I'm not very good on Amanitas

)

Found in dense continuous bracken which was wooded 150+ years ago and has a few remnant oak stumps. Flesh not yellowing with KOH. Spores subglobose 7.4-8.7 x 5.5-6.8 Q av 1.3. Though these measurements were taken from a gill squash - I'm waiting for it to do a print which will be more accurate.

Cheers
Melanie

SheffieldLass · #2 (**permalink**) 14-10-2009, 07:43 PM

Additional information:

Amyloid spores. Spore size from spore print:
(6.5) 6.8-7.8 (8.2) x (5.2) 5.4-6.3 (6.6)um Qav 1.2

Taste:

no I didn't try .....

ManwithNoname · #3 (**permalink**) 15-10-2009, 05:05 PM

Non-striate edge to the cap, ring only slightly striate, subglobose amyloid spores and a membranous volva - doesn't leave many options, which should be good news.

I'm assuming you have ruled out Amanita citrina var. alba on the basis of the volva and lack of raw potato smell.

So you are down to a choice between Amanita phalloides var. alba and Amanita virosa. The floccose/squamulose stem is very characteristic of Amanita virosa, which would be my suggestion...

... but the spores seem to be on the small side, to say the least.

fairplay · #4 (**permalink**) 15-10-2009, 06:21 PM

Something I do not understand:
The spores from a gill squash were 7.4 - 8.7µ long, and were possibly immature.
The spores from a print (mature) were 6.8 - 7.8µ, that's about an average of a whole micron shorter.
Shouldn't this be the other way round ?

Neil.

SheffieldLass · #5 (**permalink**) 15-10-2009, 07:27 PM

Quote:

Originally Posted by fairplay

Something I do not understand:
The spores from a gill squash were 7.4 - 8.7µ long, and were possibly immature.
The spores from a print (mature) were 6.8 - 7.8µ, that's about an average of a whole micron shorter.
Shouldn't this be the other way round ?

Neil.

Not necessarily, at least with me

.... Because I'm assuming there may be immature spores with a gill squash my tendency is to go for the biggest, and with the other things in the picture the big ones are probably the most obvious too. With the spore print I always measure the ones most in focus that appear to be properly side on, and I know they are not immature either (or if it is a very dense spore print randomly drop points then choose the nearest spore that is in focus and properly aligned to measure). That way they are more representative of the size range. I do have to resist the temptation to measure the biggest, particularly as it is easy to think the smaller ones are not quite in the horizontal plane even if both ends are in focus

... guess it is human nature to go for the most obvious (biggest).

Sometimes I find the gill squash spores are under sized compared with the spore print, sometimes they are over-sized. I just know to be wary of the size that comes from one .... but measure just to give an indication in case the spore print fails, or because I'm impatient and want to get an idea for id.

Melanie

SheffieldLass · #6 (**permalink**) 15-10-2009, 07:51 PM

Quote:

Originally Posted by ManwithNoname

Non-striate edge to the cap, ring only slightly striate, subglobose amyloid spores and a membranous volva - doesn't leave many options, which should be good news.

I'm assuming you have ruled out Amanita citrina var. alba on the basis of the volva and lack of raw potato smell.

So you are down to a choice between Amanita phalloides var. alba and Amanita virosa. The floccose/squamulose stem is very characteristic of Amanita virosa, which would be my suggestion...

... but the spores seem to be on the small side, to say the least.

Thanks.

My thought was that it was going to be A virosa from the appearance of the stipe and lack of cap striations, so I did the KOH test (a few times too) but no yellowing at all of the flesh. I used 10% KOH, which I presumed was strong enough to get a reaction. I don't have anything more concentrated anyway. So maybe it is Amanita phalloides var alba. I don't know what the fresh smell was as this one went off very quickly. It was a rather nauseating smell by the time my nose got to sniff it ....

Funga Nordica have spore sizes considerably smaller than FOS, listed as 7-8um subglobose for A virosa, 7.5-9 x 6-7.5um for A phalloides so not so different from mine.

Melanie

fairplay · #7 (**permalink**) 15-10-2009, 08:45 PM

However you do it Melanie, you're far more methodical than me.

Neil.

ManwithNoname · #8 (**permalink**) 15-10-2009, 08:53 PM

Quote:

Originally Posted by SheffieldLass

Funga Nordica have spore sizes considerably smaller than FOS, listed as 7-8um subglobose for A virosa, 7.5-9 x 6-7.5um for A phalloides so not so different from mine.

You give the smaller diameter of the spores as 5.4-6.3 microns which is almost completely outside the range of both species as quoted in Funga Nordica. Funga Nordica has spore sizes smaller than Fungi Europaei. I don't think spore size is going to help with identification here. I still think the jizz does not fit Amanita phalloides var. alba, but I don't think you are going to get a firm identification here.

SheffieldLass · #9 (**permalink**) 15-10-2009, 09:06 PM

Quote:

Originally Posted by ManwithNoname

... I don't think you are going to get a firm identification here.

Ah well, the fun is in the trying ....

SheffieldLass · #10 (**permalink**) 15-10-2009, 09:48 PM

Quote:

Originally Posted by fairplay

However you do it Melanie, you're far more methodical than me.

Neil.

A Wacom tablet with pen on the screen (a luxurious bit of kit that I'm lucky to have)

... then click to export into Excel, which I've set up to work it all out, so it is very quick and easy. And I can do 20 spores in less time than it used to take me to try to chase one and measure by looking down the microscope

. And then I can line up the results alongside each other so it is quite easy to see how they vary. I guess that the mathematician in me has been a bit intrigued by the variations. Out of interest I checked to see what differences I got between measuring the same spores in sharp focus and not quite in focus. There is a bit, but not as much as it appears it might be.

I also noticed that using the pen onto a still photo on screen where I can position it very accurately gives smaller spore sizes than when I'm looking down a microscope and the spores are moving and I try to line it between the scale and judge the size. I think it is a bit like the effect of a black circle in a white surround compared with a same sized white circle in a black surround that creates the illusion that they are not the same size.

Methodical? I like that, it sounds very positive

, though perhaps it's a touch of the obsessive/compulsive with me

... Even when I know what something is I still like to measure the spores and check the micro details at least for the first few. And keep the photos for the record.

Melanie