Hello,
I repeatedly collect a foliicolous Ascobolus in one locality in Moravia (200 m a.s.l., on decaying, very wet leaves of Alnus and Salix, close to the Morava river).
First I identified it as Ascobolus foliicola, but now I am in doubts whether the identification is correct.
The features highlighted by van Brummelen as important for distinguishing A. foliicola and A. denudatus are the following ones:
* stalked receptacle (foliicola) vs. sessile receptacle (denudatus) - I would consider my apothecia rather sessile or only shortly stipitate
* margin permanently furfuraceous (foliicola) vs. soon smooth (denudatus) - here my find fits better A. denudatus
* excipular warts consisting of subglobose and pyriform cells (foliicola) vs. only subglobose cells (denudatus) - I can see a few pyriform cells, but the majority is subglobose

Ornamentation of ascospores clearly fits better A. foliicola, at least when judging from van Brummelen´s illustrations.. Their dimensions are (18.1)18.5-20 (20.4) × 9.7-10.9) µm
Q = 1.8 -1.9
Me = 19.2 × 10.3 µm
How would you determine it?
Zuzana