ID request: This specimen was collected in Malta on 30/04/2026 from the bottom of a stagnant pond. I retrieved some submerged organic debris, and on a sunken, decomposing globe artichoke I found extremely small black pseudothecia, approximately 0.1–0.2 mm in diameter.

Beyond the ID, I'm particularly interested in whether these structures belong to a truly aquatic or semi?aquatic species, or whether they were produced during the aerial phase and simply persisted on the involucral bracts before the plant material became waterlogged.

The substrate appears to have been underwater for quite some time, yet the pseudothecia were intact, firm, and not degraded as if they are truly aquatic. When opened for examination, they contained clusters of healthy muriform ascospores.

My initial thought is a species of Pleospora (or closely related genus ) and I am hoping it might be one of the aquatic or freshwater?adapted taxa, though it could also be just a Pleospora herbarum or P. graminearum that has remained viable underwater. 

Stephen Martin Mifsud, 05-05-2026 19:18

Re : Black pseudothecia on submerged foliar debris - Pleospora sp.

Since I have not found viable asci (and paraphyses) it is safe to assume that this is a terrestrial Pleospora (most likely P. herbarum) which when the substrate was trashed in the water pond and  submerged, the living component of the Pleospora died and what remained was a trapped mass of murispores inside the resistant pseudothecium.

If someone has a different interpretation and these may be an aquatic species, please let me know because I am involved in a project or a group studying aquatic fungi.