Observation 118722: Hydropus pseudotenax (A.H. Sm.) Esteve-Rav. & A. Ortega
When: 2012-12-01
Herbarium specimen reported

Notes: Found two groups, growing under Douglas firs.

Some stems have yellow fibrils at the base. Stems exuding “water” when cut.

Most spores 7 × 4 microns, strongly amyloid. Basidia 4-spored, up to 45 microns long. Cheilocystidia up to 75 microns long; stick out, but don’t form a continuous band. Pleurocystidia similar, perhaps even longer (up to 90 microns). Rather large cells in the pileipellis; their direction is confusing, sometimes they appear arranged periclinally, sometimes anticlinally.

The key in Smith’s book leads to Mycena pseudotenax and the match with the description is quite good, but not perfect. Fortunately, Smith’s claim that M. pseudotenax has nonamyloid spores has been corrected in an article by F. Esteve-Raventos and A. Ortega(http://www.landesmuseum.at/...). Then, Smith claims that the flesh is “thin, but distinctly cartilaginous, and thus causing the pileus to be very rigid”, which is at odds with what I’m observing: the mushrooms are rather fragile, stems easily split lengthwise. Finally, the shape of cystidia: in Smith’s drawings, they are almost cylindrical, without the long narrow basal part.

“Cheilocystidia narrowed towards the base” is a major test in Maas Geesteranus’s key. Assuming our mushrooms are Mycena, this key would put them in in section Calodontes, subsection Purae. However, in every Pura, with the exception of M. dura, the lamellar edge is a sterile band, and M. dura is not a good match either (spores larger, fasc. habit, white stipe).

Species Lists


in Melzer’s.
Pleurocystidia. Is this “[…] usually also with
amorphous incrustations around the necks or near the apex” of Esteve-Raventos & Ortega?
Stipe surface: simple terminal cells.
Pileipellis, tangential section @10X.
Pileipellis, tangential section @40X.
Pileipellis, radial section @10X.

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Created: 2012-12-03 03:21:39 CST (-0500)
Last modified: 2013-12-07 16:57:25 CST (-0500)
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