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A scattering of Yellow Fieldcaps

A walk though the park today I was pleasantly surprised to find many small yellow and slightly larger pale mushrooms peppered around in the short grass. And as I suspected, these were actually all the same mushroom species, just in different stages of growth.

Bolbitius titubans

Credit: Caroline Hooper, Gloucestershire UK.

The Yellow Fieldcap (Bolbitius titubans) is a very widespread and common little mushroom, fruiting during summer to autumn, but I often see them in mid-late spring time too, as in this case. It mainly frequents well manured grassland but is also found on rotting straw, manure, dung and wood chippings.

When very young, its small cap is distinctly rounded, elliptical or sometimes ball-like and is a striking bright yellow colour. It also has a slimy surface texture which sticks to your finger after a gentle prod of the cap! As is grows, the cap opens into a bell shape and eventually spreads to almost flat. During this process, the viscosity fades as well as the chrome yellow colouring until it is nothing more than a pallid straw colour or greyish-white. Some yellow however does remain (for a while) at the very apex of the cap, and the margin becomes noticeably striated and very thin.

The gills on the underside are pale yellow and quite crowded. With age these change colour too, becoming light brown and eventually rusty brown. This is a good identification feature to look out for on older specimens.

The hollow stem, just like the cap, is very fragile and is relatively long when compared to the size of the cap (this can be helpful for locating them amongst the grass to be honest). On closer inspection you’ll see it is covered in fine white powder and more downy at the base.

And as a quick sign off, it’s interesting (albeit a little confusing) to know that although the common ‘Fieldcap’ name is used, the Yellow Fieldcap isn’t actually part of the Agrocybe genus, which are commonly known as Fieldcaps. So make of that what you will!

Mushroom montage

Different ages: Bottom left – Very young chrome yellow, viscous cap. Top left – Middle aged fading yellow cap. Top right – Yellow gills mature deeper brown. Bottom right – Old and faded cap with distinct striations.

QUICK ID TABLE: YELLOW FIELDCAP Bolbitius titubans

CAP / FLESH

1-5cm across. ball shaped or elliptical and chrome yellow when young. Pallid yellow to greyish white, bell shaped to almost flat when older. Striate margin. Thin, fragile flesh.

STEM

3-10cm x 0.2-0.4cm. Pale yellow or whitish. Hollow. Covered in fine white powder. Downy base.

GILLS / SPORE PRINT

Adnate to free. Crowded. Pale yellow maturing to light brown, then rusty brown.
Spore Print: Rust brown (see how to take a spore print here).

HABITAT / SEASON

Manured grassland, rotting straw, dung, wood chip. Mid spring through to autumn.

EDIBILITY

Not edible.

Mushroom sketch - Bolbitius species

Common crumbler – The Common Yellow Russula / Ochre Brittlegill

Recently from late summer to round about now (mid-autumn) this is the most (extremely) common mushroom I find on my trips out. Well, this and the Sulphur Tuft, which is as common as muck but a lot prettier!

The Common Yellow Russula or Ochre Brittlegill (Russula ochroleuca) is simply everywhere. Sometimes in small groups scattered across the woodland floor (all types of woodland) and sometimes simply on their own. What a popular fellow (no tree pun intended).

Young Common Yellow BrittlegillThe Russula family of fungi is simply huge, consisting of more than two hundred species. Their commonly used name is the Brittlegills. If you run your finger across it’s white, widely spaced gills with light pressure they will buckle and break very easily. In fact the whole mushroom structure is brittle, or for want of a better word ‘crumbly’. This genetic characteristic is a useful identification tip in recognising all Russulas (Please note that the Charcoal Burner is the exception to the rule with it’s gills being quite flexible and resistant).

With so many Russula mushrooms lying about, all with their own distinctive colourings, there are (you’ve guessed it) more yellow chappies out there to add to the confusion. Mushrooms don’t ever make thing easy do they!? The most common twin is the Yellow Swamp Brittlegill (Russula Claroflava) which is definitely more tasty than our common friend here. It has a brighter yellow coloured cap and is found only in moist, damp birch woodland. The spores are ochre coloured as opposed to the white/cream spore print of the common species.

As mentioned above, the Yellow Swamp Brittlegill is a better edible find but I have no good photos of it yet to show you – that’ll be for another day in the diary I think. But none the less, I did try our common friend here – and although not highly rated – I didn’t think it was that bad. It is a little bitter, but it can be nice and fleshy and would be quite good if added to a multi-mushroom dish with good seasoning. Give it a try.

One last tip before you take these mushrooms home is take a good smell test. Just in case you have a Geraneum Scented Brittlegill (Russula felea) on your case. It is very much unpleasant and bitter to eat. So, just as you wouldn’t geraniums – don’t eat mushrooms smelling of them. Good rule!

Common Yellow Brittlegill

Not often will you find a prisitine specimen. Russulas are fragile things, and most loved to be nibbled and munched!

QUICK ID TABLE: COMMON YELLOW BRITTLEGILL / OCHRE BRITTLEGILL Russula ochroleuca

CAP / FLESH

4-10cm across. Initially convex, then flatenning out, often with a depression. Ochre, yellow or sometimes greenish-yellow. Two-thirds peeling. Flesh tastes mild to moderately hot.

STEM

4-7cm x 1.5-2.5cm. White. Turns grey-white with age.

GILLS / SPORE PRINT

Adnexed. Creamy white.
Spore Print: Whitish / pale cream (see how to take a spore print here).

HABITAT / SEASON

With broad-leaved trees and conifers. Late summer to late autumn.

EDIBILITY

Edible. OK.

The Genus RUSSULA (Brittlegills): Characteristics to look out for:

• Simple stems with no ring or volva.
• Many have bright colours in shades of red, yellow, greenish and purple (or mixtures of). A few are pallid.
• Whole fruting body is ‘brittle’ (granular and fragile) and will easily crumble, break on handling.
• All have straight (precise geometric look) gills. These crumble (on all but one species) when touched/handled; hence brittlegill.
• Note how much the cap cuticle/skin ‘peels’ from the margin upwards (.ie. 1/4, 1/2, 3/4 or none etc).
• Note smells and tastes of hot, bitter or mild from nibbling & spitting (be sure you’re dealing with Russulas!).