Dear all,
I have been going through herbarium specimens of Ulota in search of bryophilous ascomycetes for the past week. The following fungus is represented in 2/60 vouchers examined so far as well as one recent collection by me where living material was briefly examined. I have struggled to place this collection in taxonomic context and was hoping for suggestions.
Fruitbodies solitary or gregarious, superficial, hairless, dull orange at first but turning dark grey with age, around 125 - 200um with round ostiole 17 - 21 in diam. Excipulum dense, not yet examined by sectioning.
Most material has been too scarce to make good measurements. I can include these later if they would help, though I think this species is currently undescribed so they are probably not much use.
Asci octosporous, bitruncate, variable in width, blunt-ended, hyaline, reacting J+ blue at the tips in Baral's Iodine (very difficult to see in images). Paraphyses / paraphysoides difficult to visualise, seemingly forked at the base, 1.5-2 wide, slightly longer than asci with some kind of Iodine-staining bodies in them.
Ascospores hyaline, dense with guttules, particularly in the living collection which obscures the septa, consistently 3-septate when mature, slightly constricted at middle septum. Guttules disappear in Lactophenol Cotton Blue and have receeded but not disappeared completely in herbarium material.
Hyphae pale brown, superficial, thin-walled, septate. Appressoria not yet identified. I think I have visualised haustoria in several cells as shown in images. The nutrition seems to be necrotrophic based on my recent collection, as host plants were turned grey when colonised. This is in contrast to the usual brown colour of older plants of this moss.
There are some similarities in the microscopic structures to the following species found on related hosts:
http://www.ascofrance.com/forum/55767/orange-on-ulota-crispa
However, this species is perithecioid so I am skeptical that it is related to Belonium coroniforme.
Any pointers would be very much appreciated.
Thanks,
Georges