Posts tagged moisture oontent

Suillus species- Slippery Jack et al.

suillusThis fungus is always associated with pine trees and emerges in huge numbers in pine forests all over the country.   There are two common species, S. granulatus, the normal one where I am and S. luteus, which is more common up near Perth.  The main difference is that the former has no ring on the stem.

Although this mushroom is much collected by people of European background, and turned into pickles,  it is not something that I am fond of.   I find that it leaves a rather unpleasant after-taste.   It is usually peeled and it benefits from drying out before use in cooking to prevent it turning into a slimy mess.

Footnote:  I tried some S. luteus last night (25 April, 2010) in a kind 0f stroganoff.  The dish was pleasant enough, but the after-taste was there again, lingering for a couple of hours.  It is a pity, as these are so plentiful.

Footnote 2: 20 June 2015.  The practice of peeling slippery jacks appears to have a sound basis.  This report indicates that the slimy cap contains a rather strong toxin that is heat stable and not extracted by boiling water.

Footnote 3: 28 April 2016

There has been some suggestion that smaller specimens are firmer than larger specimens.  To investigate this, I picked some fresh S. granulatus and dried them on a wire rack over the wood stove, without peeling them.  The results are shown in the graph below.   It can be seen that there is a clear linear relationship between the wet and dry weights and that the dry material is about 6.5% of the wet weight.  In other words, they are 93.5% water.  In other words, there is no evidence that the smaller specimens are more solid than the large ones.

None of the specimens appeared overtly wet.  Perhaps if there had been more rain, they might have had a higher moisture content.   By comparison, oyster mushrooms are reported to have between 70 and 95% moisture contentAgaricus bisporus is reported to have a moisture content of between 88.6 and 91.3 percent.  That means that the Agaricus mushrooms are about 60 percent more substantial than the Suillus.

moisture content

There are quite a few different species of Suillus to be found in the pine plantations of Western Australia. These include: Suillus luteus, Suillus quiescens, Suillus salmonicolor and Suillus collinitis. There are others that are difficult to identify to species level without DNA work. Below are a few examples of some that I have found.

Suillus salmonicolor

This one grows in one particular area of one pine forest and I have not been able to identify it. I have named it ‘silverback’ because of the silver grey colour of the cap.

Suillus ‘silverback

Suillus species display a range of colours. This one had bright red staining on the stipe and a light blue on the flesh inside the cap.

Suillus ‘red and blue
Suillus ‘dotty’

The spores of Suillus are rather acicular. Below is an image of the spores of what I believe to be Suillus quiescens. The size is 7.1 x 2.7 microns.


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