Blue Roundhead / Summer / Autumn / Inedible

The Blue Roundhead (Stropharia caerulea) is a captivating with its striking blue-green hues. Commonly found in grassy areas, woodchips, and leaf litter across Europe and North America, this eye-catching fungus stands out due to its vivid colouration and distinctive round cap.

The Blue Roundhead features a smooth, slimy cap that can range from bright blue to greenish-blue, with a sturdy white stem adorned with a delicate ring.

As a member of the Strophariaceae family, this mushroom plays a crucial role in decomposing organic matter and enriching soil health.

In this blog post, we will delve into the unique characteristics of the Blue Roundhead, provide tips for identifying it in the wild, and discuss its ecological importance.

Common Names

Blue Roundhead

Scientific Classification:

Stropharia caerulea

Kingdom:

Fungi

Order and Class: 

Agaricomycetes, Agaricales

Family: 

Strophariaceae

Genus: 

Stropharia

Growing Season of the Blue Roundhead:

Depending on where you are in the world, this mushroom is an earlier bloomer often popping up across Europe from late spring in July, well into the autumn months in November. In some areas such as North America, this mushroom can display shorter growing seasons from August to October. 

Habitat:

Blue Roundheads are considered a saprobic fungus (collecting nutrients from consuming rotting organic matter) so are commonly found developing in small groups. This fungi loves beech woodlands, but can also be discovered growing in grasslands and heaths.

Physical Characteristics of the Blue Roundhead (Stropharia caerulea):

Cap 

As the name suggests, a good identifying feature for this mushroom is its blue coloured cap, presenting more yellowy green hues in the centre as they age. The shape of the cap is convex on young species, which turns into a bell-shaped cap just before it flattens out as they fully mature. It has a slimy exterior ( which can dry out in the sun) with possibly a few white scales as the young mushrooms grow out of their veils. 

Gills

The adnate gills are whitish brown and light in colour when young. As they age, they get darker and can develop more purple tones. Spore print: purplish brown.

Stem

The scales on this mushroom continue up the stem starting at the base but are interrupted by a ring, leftover from the veil. Near the exposed gills, the stem should be smooth in appearance. 

What can the Blue Roundhead be Confused with:

The Blue Roundhead (Stropharia caerulea) can be mistaken for several other mushrooms due to its distinctive blue-green colouration and habitat. Here are some common look-alikes and the key differences to help in accurate identification:

1. Verdigris Agaric (Stropharia aeruginosa)
   • Appearance: Similar blue-green colour, slimy cap, and white stem with a ring.
   • Key Differences: Verdigris Agaric is typically more vibrant and shiny, with a thicker, more pronounced stem ring. Its cap often has a more uniform blue-green colour compared to the sometimes patchy appearance of the Blue Roundhead. It can also exhibit more prominent white veil remnants on the cap margin.
2. Parrot Waxcap (Gliophorus psittacinus)
   • Appearance: Bright green to yellowish-green cap, often with a slimy texture, and a slender stem.
   • Key Differences: The Parrot Waxcap is smaller, with a more delicate and slender stem, and often displays a wider range of colours, including yellows and oranges as it ages. Unlike the Blue Roundhead, it lacks a stem ring and is typically found in mossy or grassy habitats rather than woodchips or leaf litter.
3. Blue-Green Brittlestem (Psilocybe cyanescens)
   • Appearance: Blue-green to brownish cap, sometimes with a slimy surface when wet.
   • Key Differences: The Blue-Green Brittlestem is known for its bruising blue reaction when damaged. It has a more delicate, fragile stem without a ring and is often found in woodchip mulch or decaying wood. Its cap is typically smaller and more conical compared to the more rounded cap of the Blue Roundhead.
4. Blue Pinkgill (Entoloma hochstetteri)
   • Appearance: Striking blue cap and stem, with a more fibrous texture.
   • Key Differences: The Blue Pinkgill is a more uniformly blue mushroom with a fibrous, rather than slimy, cap and stem. It also lacks a stem ring and has gills that are more pronounced and can turn pinkish with age. This species is more common in New Zealand and less likely to be found in Europe or North America.

Edible Uses:

Inedible – causes stomach upset.

Other Facts:

Research in the past has pointed to this mushroom as containing compounds which cause hallucinations, but this was proven to be incorrect in more recent studies.  

References:

more about the blue roundhead