Observation 10762: Agaricus L.

When: 2008-09-09

Collection location: Hershey, Pennsylvania, USA [Click for map]

Who: James V. Gallagher IV (lbjvg)

No specimen available

location: beneath hardwoods.
Cap: convex, white with brown at top
Stem: Equal, curved, small bulb
Gills: pinkish, close, free
Spores: dark brown

I didn’t really notice any bruising reaction.


grams iodine

Proposed Names

75% (2)
Used references: Key based lookup. Young Agaricus tends to have pink gills, and Agaricus has brown spore print and free gills.

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= Observer’s choice
= Current consensus


Add Comment
By: Paul Derbyshire (Twizzler)
2008-09-10 09:33:28 CST (+0800)

Yet you got a powdery spore print before the dissolve? This would suggest Agaricus; if the spore print was gooey, it suggests Coprinus instead, particularly combined with the conical cap and appearing near wood.

ring, dissolve
By: James V. Gallagher IV (lbjvg)
2008-09-10 09:26:30 CST (+0800)

My impression is that there is a ring. The cap dissolved into a flattened piece after about the second day of making the spore print(not pictured).

By: Paul Derbyshire (Twizzler)
2008-09-10 09:11:41 CST (+0800)

The new photos show the gills pink, then brown after the spore print was taken. This is strongly indicative of Agaricus. The apparent lack of a ring is very odd, but it may have fallen off or been lost during handling or due to weather.

By: Paul Derbyshire (Twizzler)
2008-09-10 08:51:31 CST (+0800)

Is that a ring on the stem? If so, the loose appearance of it, plus the general appearance of the fungus, almost suggests Lepiota, but the spore print rules that genus out conclusively. Chlorophyllum would have greener gills and spore print.

If there is no ring, then it seems it cannot be an Agaricus. Coprinus may have pink free gills but would dissolve rather than yield a dry spore print. It would be something obscure from Agaricaceae in that case. Entoloma would have pink gills but they’d be attached, not free.

Phaeocollybia may have free gills but tends to occur in large groups, and has deeply rooting stem. It would lack a ring. Melanophyllum has paler spore print but it may darken to cinnamon with time. How quickly did you observe the spore print after starting it? Pluteus has paler spore print and grows on wood.

This doesn’t look like a classic Agaricus, but it’s difficult to find anything else for it to be with the combination of free gills and brownish spore print.