Observation 18923: Gerronema Singer

And one more for good measure. These were also definitely attached to wood. They are larger, grayer, and have more of a silky-striate texture to the surface. Failed to get a detectable spore print, and these were fairly fresh still by time I laid them out, so I assume the print must be white.

(number 0226.10, page 162)

Added notes from 20090404:

Clamp connections clearly present. The pileipellis is a parallelocutis; all hyphae colorless. I don’t recognize the type of gill trama — gelatinized maybe? Basidia only have two spores. No cystidia on gills. I don’t have access to Melzer’s; in Lugol’s solution the spores are unreactive (basidia and the rest of the gill tissues stain deep golden). Spores are smooth and ellipsoid, about 5-6 × 4 µm.

Species Lists


Clamp connection in pileipellis (in water at 1000x).
Radial section of pileipellis (in water at 1000x).
Basidia on face of gill (vertical section in water at 1000x).
Inamyloid? spores on face of gill (stained in Lugol’s, at 1000x).
Cross-section of stipe, in water, stained with Lugol’s, at 400×. Shows sarcodimitic tissue.

Proposed Names

28% (1)
Recognized by sight
62% (3)
Recognized by sight

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Add Comment
Does this help?
By: Jason Hollinger (jason)
2009-04-05 15:06:50 CST (+0800)

(Added photos and microscopic observations at bottom of notes.)

By: Christian (Christian Schwarz)
2009-04-03 14:03:08 CST (+0800)

I’ll check about my e-mail, and thanks for the name! Someday I hope to lurk under the mighty Gunnera myself…

Here’s some diagnostics from the discussion section of an article by Banares, Beltran, and Bon in Mycologia (describing G. wildprettii from Costa Rica).

“[This taxon can be recognized as] Gerronema … by its sarcodimitic tissues, spore powder white, spores inamyloid, clamp connections present and lacking intraparietal or incrusted pigments…”

If you check the pileipellis, you should be able to find whether or not there are clamps and incrustations.

Determination of amyloid spores is easy if you have Melzer’s handy.

Sarcodimitic tissues are a little finickier to find and recognize – they look like long, smooth “stand-out” hyphae, often (always?) without septations. Try the gill trama and / or a cross section of the stipe.

Cheilocystidia would be interesting to look for… rare for Gerronema, but apparently more common in tropical members.

I have a dried specimen in front of me…
By: Jason Hollinger (jason)
2009-04-03 10:52:51 CST (+0800)

…and a microscope (that’s key). What should I look at?

(Incidentally, Christian, something screwy seems to have happened to your email address. You sent me a question about the Gunnera tinctoria leaves in my mugshot the other day but I have no way of responding! Did you change your email address in your MO preferences recently?)

that inrolled cap is curious.
By: Debbie Viess (amanitarita)
2009-04-03 10:38:54 CST (+0800)
By: Christian (Christian Schwarz)
2009-04-03 08:44:01 CST (+0800)

As silly as speculation without microscopy is, these look like Gerronema, although some fungi formerly in this genus are in a few other genera now…