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Branching Out – The Branched Oyster Mushroom

Luck was on my side this Saturday as I walked in one of my favourite woods. Stepping aside to give a couple some more room on the path, I just caught a glimpse of something white hiding beneath the undergrowth. Was it litter or was it a mushroom? You’ve always got to take a look…

Pleurotus cornucopiaeOn a fallen branch of a deciduous tree (I’m not sure which to be honest – I was too excited to notice!) was a small stout and proud group of Branching Oyster Mushrooms (Pleurotus cornucopiae). A couple were damaged but there were some great specimens with younger ones just poking below the senior ones. They were cute!

I don’t come across many Oyster mushrooms at all. Maybe that’s just Leicestershire, who knows? But this find was new to me, albeit being a moderately common mushroom. It had had it’s day during the period of Dutch Elm disease in the UK but nowadays is declining but still widespread.

I knew I was dealing with an Oyster mushroom of some sort. Looking at all the immediate visual features I was pretty sure what it was.

Unlike the typical Oyster mushroom (Pleurotus ostreatus) which has many colour variations, it is actually never white. So that ruled that out. But as the Branched Oyster matures further it does turn more towards ochre brown. Something to be aware of I think.

The other main feature was of course the stem which is very apparent. Many typical Oyster mushrooms have little or no stem to show, but in this case it was an interesting identification feature. It also has an ‘off-centre’ position in relation to the cap. The cap sinks into this stem in a similar way to a typical ‘Funnel Cap’ mushroom with very decurrent gills. In fact, if the stem was central and this mushroom grew from the ground you would think you were looking at a Funnel mushroom! Anyway, I digress, you get the picture…

To elaborate on the colour (mentioned above) this mushroom is initially white/cream, covered in a whiteish bloom, and in time will have an ochre tint, eventually becoming completely ochre-brown. Other features include the cap itself becoming wavy and often split a the margin, as shown here in the various pictures.

And if you do (or even have) found any of these beauties you may see them growing sideways out from the wood and the stem curve so the cap is level with the floor. In this case, I think they were lucky to be facing skywards due to the fallen branch. The stems usually ‘fuse’ together at the base. Again, in this case, only a few were fused together when I found them, and the larger ones were on their own. Different finds sometimes show slightly different results. Good points to take note of.

White Oyster Mushroom

QUICK ID TABLE: BRANCHING OYSTER Pleurotus cornucopiae

CAP / FLESH

5-12 cm accross. Initially convex/rounded then funnel-shaped. Margin often splits. Cream coloured with white bloom turning ochre brown with age. Smell is of flour or slight ammonia.

STEM

2-5 x 1-2.5cm, off-centre. usually fused with others at the base. Whiteish. Ochre tinge with age.

GILLS / SPORE PRINT

Very decurrent. White and/or pale pink in colour.
Spore Print: Pale lilac (see how to take a spore print here).

HABITAT / SEASON

In grouped clusters on stumps or dead wood of deciduous trees (esp. elm or oak). Spring to autumn. Occassional.

EDIBILITY

Edible. OK.

The Genus PLEUROTUS (Oyster): Characteristics to look out for:

• Shell shaped fruting body, often with little or no visible stem.
• Growing on wood in clumps/dense groups
• Very decurrent gills.
• Spore print ranges from white to pale lilac.