Archive for Fungi

Anatomy of a Yellow Stainer

Within the genus Agaricus, the Section Xathodermatei contains a number of species that are commonly known as yellow stainers and they are known to contain phenol which causes quite nasty gastric upsets if consumed. I have been meaning to put together a post about these but it was only this morning that I found a substantial patch of them on a street  verge to do some images and experiments.  A few members of the patch are shown in the picture below.

Yellow stainers on street verge

 

The yellow staining reaction is seen both on the cap and on the stem of the mushrooms and manifests itself as a bright chrome yellow stain that quickly fades. Once picked, the yellow stain on the cap may not continue to show itself. The picture below shows the sort of stain that occurs when you first pick one of these mushrooms. This was completely gone within 2 minutes.

yellow stain on cap

Yellow stain on edge of cap when first picked

 

The partial veil on these mushrooms has a fluffy appearance that I believe can be called flocculose.   The appearance of the partial veil at various stages is shown in the following set of images.

Partial veil at various stages of growth

The yellow stain on the cut stem can also been seen in these images as can the white core in the centre of the stem, a feature that is also seen in supermarket mushrooms.

Another feature that tends to be a characteristic of mushrooms in this Section is the ‘boxy’ cap shape.   That shape can be seen in the first image above.  This is where the analysis gets interesting.  As I have mentioned elsewhere, the yellow stain can be made permanent on these mushrooms by applying an alkali.  The yellow colour is due to 4,4-dihydroxyazobenzene.    While looking closely at these mushrooms I noticed that they have a very distinct internal structure featuring a very dense section in the cap above the stem.   This is revealed in a sectioned piece developed with Napisan solution which provided the necessary alkalinity and perhaps some oxidizing power that might have had an effect.   An example of a sectioned mushroom developed in this way is shown in the pictures below, compared with a supermarket version.

Yellow stainer (top)  compared with normal supermarket mushroom (bottom), both developed with Napisan solution

In this view it is immediately apparent that there is a significant difference in the internal structure of the two mushrooms.  The hard core in the centre of the cap of the yellow stainer shows up clearly.   I strongly suspect that this structure is responsible for the boxy shape of these mushrooms.   Beyond that however, the flesh of the cap of the yellow stainer remains refractory to the effects of the Napisan while the flesh of the supermarket mushroom saturates and slightly darkens.   The hard core also influences the way the cap separates from the stem.   In the case of the supermarket mushroom the separation is very clean but in the case of the yellow stainer the stem breaks away with a rather ragged edge, as shown in the picture below with two yellow stainers on the right and two supermarket varieties on the left.

Cap separation on supermarket mushrooms (left) versus yellow stainers (right).

I have in mind a few more experiments on these interesting mushrooms but I will finish this post off for now.

A quick postscript.  After about an hour the difference between the two mushrooms became even more stark.

 

Advertisements

Leave a comment »

Lactarius deliciosus – Saffron milk cap – an east coast favourite.

Leave a comment »

Calvatia fragilis – another edible puffball

While driving around in April, I noticed for the first time this year some rather large puffballs growing around the place.  Here is what they looked like.

puffball

Calvatia fragilis

When cut open, these revealed a firm white flesh with a pleasant mushroom smell.  They lacked a ‘sterile base’ which is the bit at the bottom close to the attachment point to the ground.  The lizard skin pattern was also distinctive.  On standing, they developed a purple spore mass.  All of these factors together led me to identify them as Calvatia fragilis, which was subsequently confirmed by DNA analysis (97% AJ684871).

The picture below shows the specimen torn open.  There is a slight yellowing when it is bruised. It has a distinct skin.

Calvatia fragilis torn open

Calvatia fragilis torn open

The next picture shows another view of the surface of the puffball.

Surface of Calvatia fragilis

Surface of Calvatia fragilis

Some people say that all white puffballs in Australia are edible.   This is not true as many years ago I found a massive white puffball growing next to a mulga tree in Hopetoun that had an extremely unpleasant smell.  When I heated some up it caused us to evacuate the kitchen!

Calvatia fragilis is edible though and I sliced this one and fried it in butter.  The taste reminded me a little of eggs.

Comments (2) »

Rhizopogon – a taxonomic challenge

A walk in a pine plantation in WA during winter will often reveal a truffle-like fungus lying on the top of the ground or sometimes almost buried.

rhizopogon-pseudoroseolus

Rhizopogon pseudoroseolus

This is Rhizopogon, introduced with the pine trees and a very effective fungus for assisting the pines to grow.  The mycelium from fungi such as these acts as an extension of the roots of the trees, drawing in nutrients that would otherwise be unavailable to the trees.

Many sources report that the species occurring here are Rhizopogon luteolus but DNA results on the specimen pictured above match R. pseudoroseolus (GQ267483).  This species, an introduction from the USA is also very common in New Zealand, though the appearance does not appear to match either the image nor the key published by Jerry Cooper of the Fungal Network of New Zealand. There are many different species, lots of variability and many published revisions of this genus so it does make identification difficult.

In Japan, a member of this genus, Rhizopogon roseolus is much prized as a food where is it known as Shoro.  The Kiwis, always much more proactive on these matters than we are, have done some comparisons on the species growing in New Zealand with those in Japan and have gone so far as introducing the Japanese species into NZ as a potential agricultural product.

This is not an easy fungus to identify visually and there is sparse information about edibility.  My friend Jsun has eaten a species that grows in Queensland and while visiting here he pickled some that I had collected.  These are shown in the picture below.  He has selected specimens that were firm and had a white interior when cut in half. When pickled, the outside became quite distinctly reddish.

rhizopogon-jar

Pickled Rhizopogon pseudoroseolus

I have eaten small quantities of these and must say that they are rather bland. Jsun reports that he likes to add them to stews and so forth and that they soak up the flavor of the dish.

See also: https://mushroaming.wordpress.com/2015/12/26/rhizopogon-rubescens/

Leave a comment »

Laetiporus portentosus -White punk, poor tucker indeed

There have been many reports from the times of early European settlement, all from Tasmania, of the Aboriginal people eating a white’ punk’ growing on trees.  It has been widely assumed that this is Laetiporus portentosus, formerly known as Piptoporus portentosus.

This June I chanced upon a specimen of this lying on the ground in Bridgetown.  It was quite a massive thing, weighing several kilos and it was saturated with water.  That is why I assume was on the ground, having fallen from its position because of its weight.  Here it is sitting on my dining room table.

Laetiporus portentosus desk

Fallen Laetiporus portentosus on table

 

Here is another shot of it, this time showing the inside after I had cut it open with great difficulty.  I don’t think this would have been possible with primitive tools.

Laetiporus portentosus cut

Laetiporus portentosus cut open

You can see that the inside looks sort of cottony.  In fact it more closely resembles polystyrene in texture.  An attempt to eat a small piece of it revealed that it was about as edible as polystyrene too.  Not even in an emergency could anyone possibly eat and digest this fungus.  Perhaps the story is different with very small specimens but I am doubtful.

It is quite difficult to get a picture of one of these in-situ on a tree because they tend to grow quite high up.  I was lucky enough to spot one by a road cutting near Donnybrook that enabled me to scramble up and take a picture with my phone.  Here it is.

laetiporus donnybrook

Laetiporus portentosus in situ

The fact that these are relatively few and far between and so high up on the trees is further evidence against them being used as food.

It is however widely reported that they were used as tinder and to carry fire.  Some experiments revealed that a dried specimen could be ignited very readily and that it would smolder for a long time.  By judicious control of the fire front on a smoldering specimen it could easily be kept aglow for hours.  Uncontrolled burning of half a specimen lasted about 40 minutes.  I made a short video of a small piece smoldering after it had been ignited. A still from that video is shown below.

laetipurus glowing

A piece of Laetiporus portentosus smoldering

 

Leave a comment »

Macrolepiota clelandii – not for the moment

This is a common mushroom around the karri forest and other places during the early part of the rainy season.  It used to be listed as Macrolepiota konradii in guides until quite recently until Else Vellinga renamed the group in 2002.  Almost all sources list this as edible, except for Tony Young who says that this Australian species is of unknown toxicity.

IMG_0725

Macrolepiota clelandii

Its edibility seems to be  based on the fact that is was thought to be the same as the edible M. konradii from Europe.  Since this is now thrown into doubt, if not thrown out completely, I think it a wise precaution to avoid it.  Besides which, I have a general aversion to Chlorophyllum and Macrolepiota due to the fact that they sometimes cause inexplicable gastric distress.  I am sure that some people do eat or have eaten these though, so I list it here for completeness.

Here is a picture of the top surface.

IMG_0717[1]

Macrolepiota clelandii top surface

It is a rather pretty and delicate mushroom that will sometimes spring up in the oddest places.   I had one come up once half way down a post hole that I had left open. The specimen pictured is about 150mm high with a cap 100mm across.  That is a typical size.  They don’t occur as a small mushroom.  In fact, there are some small Lepiootas that look rather similar and some Lepiotas are deadly.

So I will abstain for the moment.

Update: August 2016

My fellow blogger Jsun and I picked some of these during July and he was able to confirm that they were the same as those he had eaten in the east.  I watched him cook and eat some and being thus encouraged I had a small portion myself.  I am now much more confident about these.   One thing he pointed out to me was the ‘snakeskin’ pattern on the stem which also flares out at the base.

 

snakeskin

Snakeskin pattern on stem

The ring or annulus is quite distinctive also,  breaking up in radial splits and being attached at first, but moveable with some encouragement.

macrolepiota ring

Detail of ring

Comments (1) »

Leucoagaricus leucothites -with caution

Leucoagaricus

Leucoagaricus leucothites

 

 

Leucoagaricus leucothites was formerly called Leucoagaricus naucinus and with the state of flux in taxonomy at present, it might have another name next year.  It is a mushroom of worldwide distribution, widely known as an edible species but often recommended as a species to be avoided because it shares so many features with a couple of deadly Amanitas. For this reason nobody should attempt to eat these unless they are completely confident in being able to distinguish an Amanita.

I spotted the specimens above by the side of the road, which is a common place to find them.  The caps are bright white with a satin texture.  The shape of the large specimen in the picture is characteristic of this species.   The underside features a hollow stem that widens a little at the base, but does not have a sac or volva like Amanita or Volvopluteus.  The gills are at first white but darken a little at maturity. The spore print is bright white.

It is always a little scary eating something new but even more so when it is something with white gills and a white spore print.   Nevertheless, after much checking and re-checking I fried some up and did a taste test.  From descriptions elsewhere I had expected something more; it tasted just like Volvopluteus gloiocephalus.  The mature specimen even looks a little like Volvopluteus.

One can only wonder how species like this manage to spread so far and wide.   Apparently the spores of this one germinate very readily in a wide range of media so perhaps that has something to do with it.  Anyway, another of our introduced species that is edible for what it is worth.

Comments (1) »