When: 2008-04-18

Seen at: Santa Rosa, Sonoma Co., California, USA [Click for map]

Who: Darvin DeShazer (darv)

Specimen available

Growing on Lactarius deliciosus.
Collection # DD 637
Brought to the SOMA meeting for an ID.
More photos of the Hypomyces at observation 7330

Last three photos are acanthocyte cells found on the Hypomyces. Perhaps they are made by the Lactarius in response to the attack of the ascomycete. I was unable to trace there origin and the middle photo shows the point of attachment that is broken off. The Mycotaxon article referenced below by Farr shows how they grow. The literature shows them on Stropharia and also something similar on Coprinus comatus. I could NOT find any reference to Lactarius or any species of ascomycete.

An excellent photo of acanthocytes by George Barron.

Species Lists


Spore measurement 22 µm at 400X. Each division = 3.367 µm.
Spore measurement 22 µm at 400X. Each division = 3.367 µm.
Spore measurement 22 µm at 400X. Each division = 3.367 µm.
An acanthocyte at 100X.
An acanthocyte broken off at 400X.
An acanthocyte.

Proposed Names

86% (1)
Recognized by sight
Used references: Farr, David F. 1980. The Acanthocyte, A Unique Cell Type in Stropharia (Agaricales).  Mycotaxon 11:241-249.
Hong Luo, Yajun Liu, Lin Fang, Xuan Li, Ninghua Tang, and Keqin Zhang. 2007. Coprinus comatus Damages Nematode Cuticles Mechanically with Spiny Balls and Produces Potent Toxins To Immobilize Nematodes. Appl Environ Microbiol. 73(12): 3916–3923.

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Add Comment
By: Darvin DeShazer (darv)
2008-04-23 10:02:20 CDT (-0500)

Contamination by vascular plant tricomes (hairs) has also been suggested as a possibility by Dr. Largent, but so far, none found seem to match.

By: Debbie Viess (amanitarita)
2008-04-23 09:14:52 CDT (-0500)

I can see where the acanthocytes would inhibit insect predation, but how would it affect another fungus like a hypomyces? Very bizarre that you found these structures in a Lactarius; could they be related to substrate or mineral content of the soils where the mushrooms grow? What would create these crystalline structures, anyway (yeah I know, Calcium crystals, but WHY are they crystallizing?). And according to your Mycotaxon article, they are found primarily on the vegetative hyphae of Stropharia, not the fruit bodies. Very curious.