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11-03-2026 17:36

Help for Genus and Species ID
Michel Hairaud Michel Hairaud

Bonjour, Je cherche des indices  pour cette réc

09-02-2026 22:01

Sp
ruiz Jose

Hola, me paso esta colección en madera de pino, t

11-03-2026 16:48

Saccobolus minimoides ?
Bruno Coué Bruno Coué

Bonjour, je serais heureux d'avoir votre avis sur

11-03-2026 14:14

Scopinella on Dryas octopetala
Gernot Friebes

Hi,I would like to share a collection of Scopinell

15-09-2020 17:27

Thyridaria sp.
Andgelo Mombert Andgelo Mombert

Bonjour, Sur branche morte décortiquée de Berbe

10-03-2026 18:08

Orange discs on Arctium
Marc Detollenaere Marc Detollenaere

Dear Forum,On stems of Arctium, I found some downy

05-03-2026 10:07

White apothecia on pine cone
Hulda Caroline Holte

Hello, I found and collected this species growing

07-03-2026 13:06

Phaeohelotium parasulphuratus ?
éric ROMERO éric ROMERO

Bonjour tous, Sur cône d'épicea fortement imbu,

23-12-2025 08:27

Hymenoscyphus?
Josep Torres Josep Torres

Hello.Small, yellowish ascomata, with very short a

28-02-2026 11:05

Peziza
Yanick BOULANGER

Bonjour à tousLe 24/02/2026 à Montmacq, devant m

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Niesslia-like Perithecia on Well Rotted Alnus Trunk
Peter Thompson, 13-05-2018 12:43
Hello Everyone,

I have found some tiny, spherical perithecia with short hairs growing on decorticated and well decayed wood from a trunk of Alnus glutinosa.

The hairs are thick walled, dark brown, with bulbous bases and rounded tips. They strongly resemble the rigid hairs of species of Niesslia, typically measuring 82.5 - 92.5 x 5.25 um. 

The spores are 8- 11-septate, filled with tiny drops in all cells and typically measuring 56 - 65 x 8 - 8.5 um. Hyaline and tapering to rounded ends. there are 8 spores per ascus. The ascus tips show no reaction to lugol.

I have attached a photo of the fruit bodies and a micro photo of the hairs, asci and spores.

I wonder if anyone has an idea as to what they might be?

Thank You,
With Best Wishes,
Peter.

  • message #53408
  • message #53408
Gernot Friebes, 13-05-2018 12:51
Re : Niesslia-like Perithecia on Well Rotted Alnus Trunk
Hi, Peter,

the ascomata and ascospores remind me of Acanthostigma – it might be worth looking into that direction.

Best wishes,
Gernot
Peter Thompson, 13-05-2018 18:36
Re : Niesslia-like Perithecia on Well Rotted Alnus Trunk
Hello Gernot,

Thank you for your reply.

Acanthostigma is an unfamiliar genus for me, so I have had a look into the options for host type and macro / micro characteristics and I now believe that my sample is A. minutum. 

Thank you for your help.

With Best Wishes,
Peter.