Observation 29140: Parasola Redhead, Vilgalys & Hopple

When: 2009-11-08

Collection location: Big Branch, Saint Tammany Parish, Louisiana, USA [Click for map]

Who: Chaz (tripper1445)

No specimen available

Proposed Names

13% (4)
Recognized by sight: not Marasmius. could be one of the copides or a Bolbitius

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Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
By: Dave in NE PA
2009-12-01 20:25:43 CST (-0600)

rather than relying upon the mostly scant definitions found in mushroom manuals, I consulted my copy of Webster’s Collegiate. Plicate: surface thrown up into parallel ridges. Pleat: something resembling a fold made by doubling material over itself. Striation: a minute groove, scratch, or channel. Sulcate: scored with longitudinal ridges. So, emphasis with “plicate” is placed upon the areas being raised. Emphasis with “striate” lies with the areas being recessed. “Sulcate” seems to be the most ellusive of these terms.

At any rate, as CureCat describes, the pleats seen in this cap (29140) are akin to a partially expanded French door (my own analogy), whereas the plicate Marasmius types show smoothly rounded ridges.

Thank you CureCat
By: Dave W (Dave W)
2009-12-01 06:56:32 CST (-0600)

for the excellent information. There is only so much that one can glean from the manuals. The “glistening specks” feature is very useful. And your description of the striations/creases seen in this specimen, as opposed to the plicate nature of Marasmius, is exactly the type of info I’ve been fishing for lately.

what she said…
By: Noah Siegel (Noah)
2009-11-30 19:41:00 CST (-0600)

of course a picture of the gills would end all questions.

By: Erin Page Blanchard (CureCat)
2009-11-30 19:30:13 CST (-0600)

Well Noah can explain why he doesn’t think it is Marasmius, and I will try and articulate why I agree…

First, the colour is less consistent throughout the pileus than I am used to seeing with the plicate Marasmius.
The tissue is not only thin, but it also appears very delicate and brittle, whereas most Marasmius have a more waxy texture that is pliable and far mess fragile.
The tissue also appears somewhat granular; if you look closely you see that the pileus is covered in what look like little glistening specks. The plicate Marasmius don’t seem to have this feature.
The striations of this collection are more creased, they have an unfolded look (which is exactly what Parasola do, as the cap expands, the pleats unfold and give it a webbed appearance), However the striations of M. rotula are undulating, more soft sloping, than sharp creases.
Lastly, and perhaps most obviously, the lamelle (corresponding with the plications) are fewer and more widely spaced with Marasmius than with this observation or Parasola.

Sorry if that was all really nebulous.

Ah yes,
By: Dave in NE PA
2009-11-30 18:38:21 CST (-0600)

the stipe for M. rotula should be very dark. Actually when I proposed the name the one thing that bothered me was that the “pleats” on the cap did not continue far enough toward the cap center. But I am still mystified as to what leads one away from Marasmius.

By: Erin Page Blanchard (CureCat)
2009-11-30 18:29:02 CST (-0600)

Well the stipe is the wrong colour for M. rotula

The stipe is also wrong for anything omphalinoid. Bolbitius is possible, but the fragile, plicate pileus really reminds me of Parasola.

What characteristic(s)
By: Dave in NE PA
2009-11-30 18:18:46 CST (-0600)

allow for the elimination of Marasmius?

Created: 2009-11-29 21:40:14 CST (-0600)
Last modified: 2009-11-29 21:40:14 CST (-0600)
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