
01-12-2023 21:54

Does anyone recognize this species? Apothecia in

04-12-2023 10:01
François BartholomeeusenDear forum participants, On a thin twig of Myrica

03-12-2023 19:21
ruiz Jose antonioHola a todos, en un talud cercano a un riachuelo,

28-11-2023 23:10
Villalonga PacoOn basic soil in humid bank, Teruel, Spain, around

25-11-2023 14:49

Very small fruiting bodies on affected leaves. Fou

30-11-2023 14:33
Béatrice Senn-Irletalll issues of Mycologia Helvetica (1983-2000) are

28-01-2014 10:50
Gernot FriebesHi,I'm looking for these three standard references

25-11-2023 18:14

higher resolution images available at inaturalist.
Hymenoscyphus sur feuille de Betula
Louis DENY,
28-09-2023 16:36
Tourbière de la Grande Pile. Haute Saône.
Blanc, diamètre 1 mm
Aques sans crochet, 100X10 µ
Spores non scutulloides (ou à peine): 14-16 X 5 µ. OCI = 5. Quelques gouttes moyennes et nombreuses petites aux extrémités
Paraphyses avec VB
Semble correspondre à H. caudatus, mais la forme des spores ainsi que leurs dimentions me semblent légèrement différentes.
En parcourant la clé de B. Declercq, j'arrive sur H. betulae, qui semble très voisin.
Merci de me faire part de votre avis
Hans-Otto Baral,
28-09-2023 17:37

Re : Hymenoscyphus sur feuille de Betula
Yes, I have some photos made by Bernard Clesse which look very much like yours and are identified as H. betulae.
In principle, your collection is H. sparsus, but that species I have mainly found on Quercus, rarely Fagus. But: one collection was on Betula (HB 866). In all these finds the lipid content of the spores is rather low, for which reason B. Declercq appears to have separated his species. Whether this is a good character I cannot tell.
Important is also that the VBs in the paraphyses are restricted to the upper 8-25 µm, with only scattered ones further down, in contrast to H. caudatus. And the contents are multiguttulate. This you can see on Boudier's plate. (see my folder sparsus).
In B. Clesse's H. betulae the VBs are more elongated and fill the entire width of the paraphysis, also they reach further down. Both is the case in your find as well.
Louis DENY,
28-09-2023 21:51
Re : Hymenoscyphus sur feuille de Betula
Merci Zotto.
Jean-Luc Ranger,
29-09-2023 08:57
Hans-Otto Baral,
29-09-2023 09:46

Re : Hymenoscyphus sur feuille de Betula
Hmm, this requires a photo of free spores in water to be sure, also spore size.
Hans-Otto Baral,
29-09-2023 12:09

Re : Hymenoscyphus sur feuille de Betula
Yes, this could fit, but one must be cautious, H. caudatus may occur with almost homopolar spores. The contents of the paraphyses seem to confirm your opinion.