From our list of favorite mushrooms, we think we needed to tell you about one of the most appreciated mushrooms in Spain. The thistle mushroom or Pleurotus eryngii . A delicious mushroom, abundant in many parts of the country (and the world) and also cultivable.
ORIGIN AND DISTRIBUTION OF THE THISTLE MUSHROOM
The thistle mushroom is highly valued and has the advantage that in recent decades its cultivation has been dominated . Even so, the flavor of the wild is still superior. The thistle mushroom is a fungus of European origin and today, there are very few places other than Europe where it has been described. Very specific points in the American continent and little else.
One of the reasons for this is that this mushroom is associated with a thistle. It literally grows from the root of a particular thistle , the Eryngium campestre. That is why the name of the species is eryngii. It is this association that prevents its distribution to other parts of the world since this thistle is only from the European continent and little else. As we can see from the map, it is mostly focused on Western and Central Europe, going east in temperate areas of Russia and warm areas of the Middle East.
The corridor thistle or setero thistle occurs in dry areas, moors and in the Castillas we are full of this type of dry landscape, of moorland . In fact, in Spain it is also known as Castilla mushroom. Also grows in praderíos or fields fallow or abandoned usually very usual places where it grows. It is a thistle with a very strong and extensive root system (several meters long) and it is very difficult to eradicate it.
Those same places where the runner thistle develops, is where we can find the thistle mushroom. The auspicious months are from early fall to late winter in warm and temperate climates. The average altitude at which it usually appears is from sea level to about 1500 meters above sea level. in small groups or individuals.
Although it develops in the neck of the thistle, mycorrhized specimens have been seen in other plants. In fact, there are varieties of Pleurotus eryngii that grow on other umbelliferous plants such as Ferula communis. In Spain it is rare to find this mushroom in the south of the country.
IDENTIFICATION KEYS OF THE THISTLE MUSHROOM
The thistle mushroom is relatively easy to identify. There are certain characteristics that make that when you see a few, you already have enough information to identify the rest from that moment on. Although there may be confusion that we will see later, it is relatively difficult to go wrong if certain recommendations are followed.
- Mushrooms young have a hat convex , but as it grows flattens and even is taking a slightly concave shape in the center of the hat.
- The hat is brown , brown, although in some specimens it can be light brown, ocher or almost whitish cream. This difference in color is what can lead to confusion that we will see later.
- The size of the hat is usually 5 to 12-14 cm in diameter . Specimens grown with selected strains and optimal conditions may be larger. Here we only talk about wild specimens.
- The foot is eccentric with respect to the hat. This characteristic is really important to rule out many other mushrooms with which we can confuse it.
- The texture of the foot is solid, a little fibrous.
- The blades of the hat are very decurrent . This means that the lamellae are integrated with the foot as an asymptote in a mathematical graph (“nerdy” analogy). A picture is worth a thousand words.
Read more >> 10 easy to identify edible mushrooms.
The confusion of the thistle mushroom with others that may be poisonous are not very abundant but we must always be careful. The only downside is that the color variation of the hat makes us confuse it. In this case, if the hat is whitish in color, it could be confused with several toxic specimens of the genus Clitocybe . One way not to make this mistake is to always collect those with dark brown hats.
PLEUROTUS ERYNGII CULTURE
Although the thistle mushroom is mycorrhized in the extensive root of the thistle Eryngium campestre , it is possible to grow it under “artificial” conditions. In fact it is made and marketed. There is a lot of research on the substrates where the mycelium is inoculated.
Initially it is usually done on wheat straw . It works well, straw is a residue of agriculture that is practically paid to be taken away, which is a very cheap substrate for this type of purpose. The problem is that due to the characteristics of the mycelium, the inoculation must be done on a sterilized substrate so that the thistle fungus does not have competition or become contaminated with other organisms (other fungi, bacteria …)
There is very curious research on the use of agri-food waste as a substrate for growing this mushroom in order to improve its production. They have been grown on brewing bagasse (after malt cooking), wheat straw (the most common), rice husk or wood sawdust. In this specific study by the University of Murcia , the bagasse from beer production was determined as the one with the best results.
WOULD YOU DARE TO GROW YOUR OWN THISTLE MUSHROOMS?
In Gardenprue we also did it but in this case for the oyster mushroom or Pleurotus ostreatus.
The steps are simple but laborious and require some material, conditions and patience, but power can be done. The main phases would be:
- Removing the spore of a thistle mushroom
- Inoculation into a rich medium where mycelium can grow. It is usually made into sterilized wheat grain (120º for an hour) with a little calcium carbonate to increase the pH to 7.5-8. Reagent strips like the ones we usually recommend can be used for soil testing .
- Ensure conditions of sterility of the medium, adequate temperature and humidity. Humid environment and a constant 25ºC with a humidity of 80%.
- Over time (between 10 and 20 days), the mycelium will have completely invaded the substrate (wheat grain).
- From here we can spread the mycelium over the production substrate (wheat straw) that must also be sterilized or at least pasteurized.
- To force the production of primordia, we must change the temperatures, light cycles, humidity and aeration, which are usually the following as a general measure:
- 12 hours light – 12 hours dark. We can do this with a timer.
- High humidity: 90-95%
- Temperatures of about 15º-20ºC
- Constant air renewals.
- In the last stages of growth it is recommended to take the Pleurotus out in the open if it is not too cold.
All this process has been very well documented in a home mode by the Madrid Mycological Society in the following pdf. A gem of experience to make the first steps of growing mushrooms.