Agaricus urinascens

Loving the Large – Macro Mushroom

We’re at the beginning of summer and have had some decent, warm sunny days and a reliable source of showers – apparently perfect conditions for this summer/autumn Agaric which has shown itself somewhat early. Great news for all foragers who fancy a fry up!

Agaricus urinascensThis small group of Macro Mushrooms (Agaricus urinascens / A.macrosporus) were found on a grassy roadside verge, not far from some fields and a small wooded area. They’re also found in similar environments such as pastures, woodland edges and grassy woodland clearings.

My initial analysis was to rule them out as Field Mushrooms as these are strictly pasture/field bound, away from the tree line. There was no stark, chrome yellow staining as I scored the flesh, so they weren’t Yellow Stainers either. Horse Mushrooms maybe?

Horse Mushrooms and Macro Mushrooms thrive in similar habitats, although the Horse Mushroom is not linked to woodland/tree situations. But they look much the same, especially when it comes to size; with an average cap diametre of 10 – 25cm. It has been known that the Macro Mushroom can grow up to a massive 30cm across – but this humble group were averaging around the 15cm mark.

Luckily, some immediate visual differences set these mushroom heavyweights apart;

The cap of the Macro mushroom is distinctively scaly with many ochre coloured patches. The margin also tends to naturally become toothed and/or split. It rarely opens to become flat like the smooth cap of the Horse Mushroom.

The veil covering the gills on the underside (when young and unbroken) shows a similar cog wheel style pattern as the Horse Mushroom but is not as defined.

The gills are at first greyish-white which then mature to dark brown, unlike the ‘white to pink to dark brown’ colour changes of the Horse Mushroom.

The Stem is distinctly scaly towards the base, and has a delicate/fine white particle coating all over. The stem on the Horse mushroom is relatively smooth.

The odour of the young Macro Mushroom is like almonds, becoming more ammonia-like with age. The Horse Mushroom has a mild aniseed-like odour.

One thing also to note though is that a variety of A.urinascens is also recognised, known a A.excellens. It’s even more of a Horse Mushroom lookalike, but is just as edible. Its cap is much smoother with only minute scales present and it does not grow as large; having only an average cap diametre of 10-15cm.

Edibility

The good news is that all of the above mentioned Agarics, with the exception of the infamous Yellow Stainer, are safe and good to eat. The Macro Mushroom has an excellent fleshy texture – and there’s lots of it. Don’t be put off by the slightly unpleasant, ammonia smell of the mature specimen, this disappears after cooking.

The taste is surprisingly mild although pleasant; similar to the button mushroom supermarket variety (a young variety of Agaricus bisporus). They’re definitely worth eating though. I always make sure I never ‘over pick’ my find and leave several behind to continue in their reproduction. Lovely.

Macro Mushrooms

Agaricus urinescens – The Macro Mushroom – Notice the yellow-brown scaling on the cap and the grainy/scaly base of the stem. The margin will become toothed or even split apart.

QUICK ID TABLE: MACRO MUSHROOM Agaricus urinascens / A.macrosporus

CAP / FLESH

8-30cm across. Initially rounded/convex. Covered in yellow-brown scales. Margin is toothed; often splitting. Smell of almonds in young specimens then has an odour of ammonia as it ages.

STEM

5-10cm x 2.5-3.5cm. Creamy white with fine white particle coating (easily removable); more scaly towards the base.

GILLS / SPORE PRINT

Whitish-grey maturing to dark brown (no pink colouring at any stage).
Spore Print: Brown (see how to take a spore print here).

HABITAT / SEASON

In small groups or even rings in pasture, grassy verges and grassy woodland clearings; summer to autumn

EDIBILITY

Edible. Mild & Good.

The Genus AGARICUS (Wood Mushrooms/Mushrooms): Characteristics to look out for:

• Many discolour yellowish, reddish or pinkish when cut or bruised.
• Those that discolour bright/chrome yellow should be avoided for consumption.
• Gills in young specimens are often pink (white in a few) – maturing darker brown.
• Make note of any smells, such as aniseed or a typical strong ‘supermarket’ mushroom smell.

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