Hi,

I have got material of two Helicogermslita species (presumably) which are causing me a bit of trouble. We collected the first species repeatedly on branches of Tilia here in the urban area of Graz over the last few years. The combination of mostly uni-peritheciate, clearly immersed stromata with whitish stromatic tissue and one-celled, brown, ellipsoid, symmetrical ascospores with a spiralling germ slit should lead to the genus Helicogermslita. However, the limits to similar genera, mainly Amphirosellinia, are a bit unclear to me. According to the key in Ju et al. (2004; Mycologia 96(6)) Helicogermslita should have superficial stromata which is clearly not the case here. Petrini (2013; Bibl. Mycol. 205) differentiates between those two genera as follows:

Amphirosellinia: "Ascospores asymmetrical, ascus apical plugs with rounded to angular bulge at upper rim, staining blue in iodine"

Helicogermslita: "Ascospores symmetrical, ascus apical plugs with flared upper rim, not staining or lightly blue staining in iodine"

The ascospores of our fungus are symmetrical (-> Helicogermslita) but the apical apparatus stains clearly blue in Melzer's reagent (-> Amphirosellinia). Not sure how to interpret the differences in the form of the apical plugs.

In any case, there are no fitting species in Amphirosellinia whereas Helicogermslita gaudefroyi seems to be a good match for the present collections (Læssøe & Spooner 1993; Kew Bulletin 49(1)). There are a few differences though: the ascospores of our species are broader than the measurments given by Læssøe & Spooner (28.4–38.5 x 19.1–21.7 vs (29)30.4–36(44) x (12)13-15(17) µm) and they have a sheath (Læssøe & Spooner: "no appendages or gel sheath observed"). Also the apical apparatus is very variable in our material and sometimes much larger than described by Læssøe & Spooner (7–10.9 x 5.6–10.2 vs 4.8–5.5 x 6.4-6.8 µm). But maybe the ascospore size of H. gaudefroyi is indeed a bit more variable than reported in literature – Björn Wergen has studied a similar collection from Austria (also on Tilia!) which looks very similar to our fungus but has better fitting ascospore measurements compared to the literature (https://www.sites.google.com/site/funghiparadise/d---ascomycota-sordariomycetes/xylariales/xylariaceae/helicogermslita-gaudefroyi-fabre-laessoee-spooner-1994). He has also observed a gel sheath which simply might have been lacking in the collections studied by Læssøe & Spooner due to the high age of the material.

There are also a few new Helicogermslita species described by Petrini (2003). I wanted to ask if anyone could send me the following paper:

Petrini, L.E. 2003. Rosellinia and related genera in New Zealand. New Zealand Journal of Botany. 41(1): 71–138.

I'm curious if anyone has encountered the presented species before and could share their experience. It seems to be a rarely collected fungus... For microphotos please check the attached PDF.

Best wishes,
Gernot

PS: The macrophotos attached to this post are not mine.