Observation 20833: Rhodocollybia maculata var. occidentalis (A.H. Sm.) Lennox

Found these during the MSSF San Jose Camp. The caps were about 7.0 cm across and the stipe up to 12.0 cm long. Just based on appearance, the consensus seemed to be that they were a Tricholoma species.
However, I later got a spore print and they were a light yellow in mass.The spores were dextrinoid (reddish brown) in Melzers. They were approx. 8.5 X 5.6 microns, elliptical, with a prominent hilar appendage(see photo).
No strong odor or taste. The flesh was white and the gills were creamy to beige with little change in age. Also the gill edges were quite eroded as can be seen in the photo.



Proposed Names

11% (4)
Recognized by sight
-25% (6)
Recognized by sight
62% (3)
Recognized by sight: The first impression, as well as my keys, leads to Rhodocollybia. I’m not familiar with this particular variety, but in this key
Rhodocollybia maculata var. occidentalis looks like a very good match.
83% (5)
Used references: SVIMS key as per Irene’s link.

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

Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
By: Johannes Harnisch (Johann Harnisch)
2009-05-07 14:30:50 EDT (-0400)

I woudner if David A looked at the spores?

By: Dimitar Bojantchev (dimitar)
2009-05-07 10:28:18 EDT (-0400)

This is very significant what Arora reports about the taste. Cyberliber has been down since yesterday, so I couldn’t read Smith’s original description. I do not have any other idea contradicting the current id at this point.

OK Doug, I concur, but that is some subtle red color!
By: Debbie Viess (amanitarita)
2009-05-07 10:17:25 EDT (-0400)

And I had to enlarge to max to see it. Thanks for a nice sharp shot Ron!

I’m sticking w/R.m.var.o as our current best name, despite those slightly weird spore shapes…

There is red.
By: Douglas Smith (douglas)
2009-05-07 05:02:40 EDT (-0400)

There are clearly reddish patches on the top of the cap. Often there aren’t clear “spots” like a leopard, but reddish patches and flushes randomly on the ’shroom. Some have clear spots, but more often than not, it is a slight reddish patch. Take a look at the cap surface, there are reddish patches in the light brown. That is what you are looking for.

In others from the Sierras it can be clearer, like with the ones Debbie found last year, there were red streaks down the stipe. And Alan found some up at Shasta last year, that had enough red he thought it was a H. purpurascens at first. These are on far on the other end, with only hints of red on the cap.

lack of bitter is no obstacle to R. maculata var. occidentalis…
By: Debbie Viess (amanitarita)
2009-05-06 21:36:10 EDT (-0400)

since Arora (MDM) states that particular variety is not bitter.

But you could argue a different ID with me over those weird spores…and no red spots.

Bitter is known to me ….
By: Ron Pastorino (Ronpast)
2009-05-06 20:43:08 EDT (-0400)
and they have been saved.
By: Dimitar Bojantchev (dimitar)
2009-05-06 20:32:45 EDT (-0400)

Please save it. Thank you Ron for making observations supported by critical information that allow us to reach depper into the analytical space.

Well ???
By: Johannes Harnisch (Johann Harnisch)
2009-05-06 20:27:09 EDT (-0400)

Can you tste bitter things?

Taste not bitter
By: Ron Pastorino (Ronpast)
2009-05-06 20:22:58 EDT (-0400)
Good point…I just tried a bigger chunk of the cap flesh and it still seems basically neutral/tasteless to me. Thanks for all the input everyone.
Taste not bitter??
By: Dimitar Bojantchev (dimitar)
2009-05-06 19:52:31 EDT (-0400)

Let me add my voice to the cacophony. Indeed, lots of things
point towards Rhodocollybia maculata s.l. But the part that
bothers me is the lack of taste, which normally is strongly and
inescapably bitter with that species. Could very well be an
undescribed species. Has it been seen before? I’d ask Desjardin
if he recalls having seen something like that.

Decisions, decisions..
By: Irene Andersson (irenea)
2009-05-06 11:01:36 EDT (-0400)

Now I have to make up my mind what to call it.. must go for var. occidentalis, when it’s so well described. Darkening cap with a well defined paler margin, the thick flesh above the stipe, longer spores than in other varieties, mainly dextrinoid. Thanks Debbie, for supporting my idea!

this is our official Sierra fake-out mushroom!
By: Debbie Viess (amanitarita)
2009-05-06 10:22:11 EDT (-0400)

I am not seeing red spots, but the rest of the features (similarity to Trichs,
erroded gill edges, striate stipe, cream-colored spore print, dextrinoid spores) all point to maculata; the curiously shaped but definitely not globose spores are a better match for var. occidentalis, if that one is still recognized.

The toothy grin it key to Rhodocollybia
By: Nathan Wilson (nathan)
2009-05-06 10:12:46 EDT (-0400)

Just to add to the list of important Rhodocollybia features for those who aren’t familiar with them, the eroded/serrated gills are an important macroscopic feature. On the microspocic level the dextrinoid spores are key.

Dunno, maybe…
By: Douglas Smith (douglas)
2009-05-06 05:15:11 EDT (-0400)

Well, that is true, but what else pops up really. This is the really common story about this one, people look it over, and over, and no name comes up, until someone finally says, well what about Rhodocollybia maculata? And then everyone says, ah! thats it! The problem is that it is too variable in body forms. I’ve seen it happen a few times now.

But with the off-white to light brown colors, the off-white spore color, the gill attachment, and the reddish patches on the cap, in the spring in that area, that all points to Rhodocollybia maculata.

That is until someone wants to find a way to suggest that there is something else, or all the variable body forms suggest more species up there. But I’m not really a Rhodocollybia type of guy, so I’ll leave that to others.

maculata group
By: Irene Andersson (irenea)
2009-05-06 04:42:20 EDT (-0400)

is OK with me..
But Doug, if this variety is a common one – isn’t it strange that no one on the MSSF camp recognized it..?

Spring Sierra fairly common species.
By: Douglas Smith (douglas)
2009-05-06 04:24:07 EDT (-0400)

In the spring in the Sierras a fairly common species is Rhodocollybia maculata, although it is very variable in its body form.

You might try and suggest there is a group of species here, but for most people these are all R. maculata. The body form is almost any size and shape, with the gills, cap, stipe, but they will be off-white to light brown. The only common feature is reddish flushes that dev. on the cap and stipe as it ages. These show these reddish flushes on the cap.

well, if we could just ignore the microscopy, I’d say Trich!
By: Debbie Viess (amanitarita)
2009-05-05 21:24:29 EDT (-0400)

do you know of a Lyophyllum with yellow in mass, smooth, dextrinoid spores that look a little bit torqued (maybe phaseoliform rather than ellipsoid?) with a prominant hilar appendage? I don’t.

the good news is…it’s the beginning of the season, and now we can all look for more!

Created: 2009-05-05 16:58:34 EDT (-0400)
Last modified: 2009-05-05 16:58:34 EDT (-0400)
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