Recently, @riverflows asked me to check her ID on the Saffron Milk Caps that she found on her trip to Tassie (she was 100% correct) and as mushrooming time is upon us in South Australia, I thought I'd share some of my foraging experience and publish a series of posts about identifying edible, South Australian mushrooms.
I thought I'd start with a look at the genus of fungi that most people think of when folks say 'mushrooms' - the genus Agaricus.
The Agaricus genus of fungi provides us with some of the best tasting and most prolific mushrooms of Winter. If you can learn how to identify the one bad one, you can be sure of a good feed of traditional white mushrooms.
We have three species of edible Agaricus around Gawler, two of which are described 2in ths series of posts (I haven't got clear pics of the third species yet but will post that one when I do). They are pretty similar and have slight differences but are all edible. There’s the Pavement Mushroom, A. bitorquis and the Button Mushroom. A. bisporus. Then there’s the slightly toxic A. xanthodermus. As long as you learn to broadly identify members of this genus and know what to look out for in a Yellow Stainer (A. xanthodermus), you’ll be right.
Agaricus have large, fleshy, white caps and are, essentially, the mushrooms that you buy from your farmer’s market or supermarket. All of the mushrooms in this genus have several features in common. There are slight variations between the species but generally, you will find –
- Broad white/brown cap
- Cuticle that is easy to peel (the cuticle is the skin of the cap)
- Crowded gills that start pinkish and become browner with age
- Brown spore print
- Thick stem with a fragile ring that is easy to destroy
- No volva (the volva is the base of the stem)
- The stem is easily separated from the cap
There is one mildly toxic member of this genus to be found locally but it is very common and easily hybridises with other, closely related, edible species so its probably best to start with learning how to clearly identify that one. Luckily, it is easy to distinguish once you get your eye in. So lets start with that one, the dreaded Yellow Stainer (A. xanthodermus)
Yellow Stainers (A. xanthodermus)
Phylum: Basidiomycota. Class: Agaricomycetes. Order: Agaricales. Family: Agaricaceae
Yellow Stainers are a very important mushroom to learn to identify because they are very similar to other local species of Agaricus mushrooms. The others are edible and delicious but Yellow Stainers are mildly toxic and taste of chemicals. They can be found in the same grassy areas as the edible species and are sometimes mixed in with them.
The general description of most Agaricus mushrooms apply to Yellow Stainers – a broad white/brown cap, a thick stem that is easy to separate cleanly from the cap and has a ring that is easily broken or removed, cuticle that can be easily peeled, crowded gills that darken with age, They also share a brownish spore print. Luckily though, there are clear differences to help you avoid picking the or, worse, eating them.
The distinguishing characteristics of A. xanthodermus mushrooms are as follows –
- Young specimens are flatter and almost box-like when compared to similar Agaricus species
- The stem is hollow on mature specimens
- All parts of the mushroom will stain YELLOW when damaged.
- The base of the stem often has a yellow tinge
- Yellowing will turn brown after time
- Gills start as off white, become pinkish and then grey-brown
- Cap does not have an in-rolled margin
- The mushroom has a chemical smell, some say like ink. This smell intensifies with cooking,
As with all things, there is some variation between individuals. The yellowing can range from pale yellow through to a bright, chrome yellow and in some specimens may not start for a couple of minutes. It always turns brown after a while. If in doubt, check the base of the stem, damage there will always turn yellow. The base may even have a yellow tint when undamaged.
Note: There are some folks who can eat Yellow Stainers without ill effects. Don’t risk it though! Poisoning will give you one to three days of diarrhea, vomiting, fever, chills, shakes, nausea, headache or any combination of those. You will generally feel lousy – I know I did! Don’t risk it, if it is yellowish and has a chemical odour, give it a miss.
Keep this description in mind when foraging for the other Agaricus mushrooms that I will be posting about. It could save you from poisoning.