Observation 196675: Pleurotus ostreatus group
When: 2015-01-19
40.26° -74.7909° 38m
Who: bon_vivant
No herbarium specimen
0 Sequences

Request for identification

I found some mushrooms growing in my yard. Here is a description of them.

• Spore Dispersal: Gills. The gills were large, and simply attached at their full dimensions and in a straight line directly to the common, fleshy mass (see below). In other words, the gill attachment was not decurrent, adnate, adnexed, free, etc. The gills ran all the way to the rims of the caps. There was a deep “groove”, each as wide as one of the gills, between any two adjacent gills, and the gills didn’t fork at all. The gills were beige to off-white, mostly light beige. (The gills were not really yellow, as they appear in one of the attached photographs; that color is just an artifact of the shot being brightened so that it could be seen more clearly.)

• Stipes (stalks / stems): None. Instead the mushrooms grew in a dense mass of somewhat overlapping caps, each attaching directly to a common, fleshy mass from which all the mushrooms grew.

• Caps: The caps were about 3 to 5 inches in diameter. There was also a mass of smaller mushrooms that appeared to be of the same species, but whose caps were only about one and a half to one and three quarters of an inch in diameter. The caps of the larger mushrooms were about one half to three quarters of an inch in thickness, including the gills.

The caps were slightly “cupped”, with the gill side being slightly concave. The caps were not completely round, since one side of each of them was growing out of the common mass that they all shared. Also, on some of the caps, the side opposite the common, fleshy mass was somewhat “flattened”, so that it was a bit closer to the center of the cap than it would otherwise have been. This flattening gave some of the caps the look of clams or some other mollusk. The rims of the caps did not turn downwards, nor were they wavy.

The tops of the caps were a uniform beige, smooth, tough and not slimey.

• Spores: There was no trace of remaining spores, so I can’t attest to their color or other attributes.

• Smell: The mushrooms had a medium-weak smell, not unpleasant, which is hard to describe but that didn’t resemble the scent of button mushrooms. I think the smell was vaguely like that of wood, or even more like that of the forest floor.

Is has been suggested by some who are a lot more knowledgeable than me on this subject that this species is Pleurotus ostreatus, the oyster mushroom. That may be so, but I have the following observation to make: according to the literature, Pleurotus ostreatus has the bittersweet aroma of benzaldehyde, and hence smells like anise or almonds (rather than like the forest floor).

• Bruising: No bruising was observed, neither on the gills nor on the tops of the caps, but the mushrooms were already quite dehydrated by the time I damaged a couple of them to test for this, so perhaps their ability to bruise may have been inhibited by this.

• Growth Substrate: The substrate in which the mushrooms were growing was coarse, porous dirt. A shrub had previously been removed from this site. I believe it was a rose bush, but I’m not sure. The dirt was derived, at least in part, from rotted wood, and some wood fibers remain in the dirt, but no solid wood remains buried beneath the surface.

Perhaps “dirt” is the wrong word. It’s very coarse and porous, with many wood fibers in it, so perhaps “wood-based compost” might be a better term. But then again, maybe such a substrate wouldn’t sustain a wood-loving mushoom species (as I believe this species must be) – I wouldn’t know.

• Habitat: The mushrooms were surrounded by lawn grass, and not near any trees, in central New Jersey at latitude 40.2600°, longitude -74.7909°, and elevation 125 ft (38 m). The temperature was below freezing most of the fruiting time (and always below freezing at night), but these mushrooms neither froze nor rotted.

• Season of Fruiting: Starting to fruit about January 10, starting to decay on January 17.

No chemical or microscopic analyses were performed.

I have attached 4 photographs of these mushrooms.

The specimens are currently still growing in my yard.

Any identification information that anyone can give me would be greatly appreciated.


batches of big and small.jpg
big cap gills.jpg
cap attachment 1.jpg
cap attachment 2.jpg
big caps 02-08-2015.jpg
small caps 02-08-2015.jpg

Proposed Names

30% (2)
Recognized by sight: Based on the cold weather fruiting and possible wood substrate, photos are inconclusive.

Please login to propose your own names and vote on existing names.

Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
Nature is powerless to stop them…
By: bon_vivant
2015-02-08 17:52:44 CST (-0500)

They simply will not die.

Here are 2 shots of the mushrooms in my front yard newly emerged from the snow, and miraculously, despite being at least a month old and buried under snow for about half that time, they’re apparently virtually unharmed. Go figure…

The 2 new shots (“big caps 02-08-2015.jpg” and “small caps 02-08-2015.jpg”) appear under Observations, as so far I have been unable find any way to append them to this Comment.

Does anyone have any idea how these mushrooms could still be alive (or at least undecayed)? I persoannly have never before seen or heard of such a thing.

By: bon_vivant
2015-01-23 17:46:24 CST (-0500)

OK, thanks for the heads-up, Dave.

Highly unlikely…
By: Dave W (Dave W)
2015-01-23 17:32:23 CST (-0500)

this collection represents either O. olivascens or C. dealbata. Aside from O. olivascens being a western NA species, it is unlikely that any Omphalotus fruiting would occur during the winter in eastern NA. C. dealbata is a smallish whitish mushroom that does not form large clusters of robust fruit bodies.

Toxic North American look-alikes
By: bon_vivant
2015-01-21 16:26:05 CST (-0500)

Could this mushroom be either Omphalotus olivascens, the western jack-o’-lantern mushroom, or Clitocybe dealbata, the ivory funnel mushroom?

Created: 2015-01-19 16:11:56 CST (-0500)
Last modified: 2015-02-08 18:00:42 CST (-0500)
Viewed: 240 times, last viewed: 2017-11-02 22:14:10 CDT (-0400)
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