17-09-2025 10:50
Heather MerryleesHi there!I am hoping for any advice on the identif
27-11-2025 15:41
Thomas LæssøeSpores brownish, typically 4-celled; 26.8 x 2.4;
27-11-2025 12:01
Thomas Læssøehttps://svampe.databasen.org/observations/10496727
27-11-2025 11:46
Thomas Læssøehttps://svampe.databasen.org/observations/10493918
27-11-2025 11:31
Thomas LæssøeCollectors notes: Immersed ascomata, erumpent thro
23-09-2025 13:31
Thomas Læssøehttps://svampe.databasen.org/observations/10534623
25-11-2025 14:24
Thomas Læssøehttps://svampe.databasen.org/observations/10490522
26-11-2025 18:13
Jason Karakehian
The entire run of Mycotaxon is now available throu
Hi to allThis fungus forms subcuticular pseudothecia (¿?) under the periderm of stems of Arundo donax. These pulvinate and ostiolate ascomata, arranged in longitudinal lines, are singly or situated on small stromata with some other ones, 0.4-1.5 mm long, up to 0.15 mm high.
The 8-spored asci are cylindrical and I think they are bitunicate altough I can see maybe a small structure near the apex. The golden brown bi-cellular ascospores and the pseudoparaphyses are showed in the pics. I tough could be a Didymella or a close related genus, but I don't know a good genus for this collection.
Have you some ides for it?
Thanks again
not sure but your fungus looks like a Roussoella. If so the spores should be delicately longitudinally ribbed, it's difficult to see if the preparation is not very thin.
The smaller spores with broadly rounded ends would fit R. donacicola (Speg.) Ju, Rogers & Huhndorf which is common on this host. The slightly larger and more narrowly elliipsoid are less typical of this species and recall a tropical species, R. chiangraina (in Phytotaxa 181(1), 2014).
Saludos,
Jacques
Hi Jacques
Fantastic! I feel you are right, although the faint striate ornamentation is hardly visible. But the rest of the generic characters fits well with this fungus.
Thanks a lot!