I measured sometimes *6-9 x 2-2.5 µm in L. virgineum, so I think this is right.
Zotto

Gracias Zotto,  siempre que la había estudiado antes las esporas eran más estrechas por eso tenía dudas.

Saludos
Javier

The length of 10 µm is possible too.

Hello,
I have a similar problem with Lachnum papyraceum collected on Picea abies (mountain forest in central Europe). Spore size in Nordic Macromycetes vol. 1 is 4-6 x 1-1.5 um; in an older description (Saccardo 1889) the length is 3-7 um.
Many spores are bigger in my collections, e.g. (6-) 8 x 2, 10 x 2 um, but some 5 x 1.5 or 8 x 1.5 also occur (these are inside asci and may not be mature). The width of most spores is rather 2 than 1.5 um. Everything else seems to fit L. papyraceum, but I do not have an experince with these species (do not have a more comprehensive key than Nordic Macromycetes).

Thanks,
Vaclav

This is mainly a problem of living vs. dead spores. Did you measure them from fresh samples in water?

The few records I have of that species vary in spore length betwee short and long-spored.
Here is an example, and I so far found no other name for it.

My spore range of the long-spored variant is:
7.5-11.7 x 1.7-2.6

Important is that the paraphyses and hairs contain strongly refractive VBs which cause the red-brown colouration in senescent apothecia.

I did not have an opportunity to microscope fresh samples. I understand now that spores and especially asci in fresh material are longer than in dry samples. I always start with water and I added Melzer's reagens to check if pores in asci turn blue. It does not seem that spore size differs in water and in Melzer in dry material. I could see granulose content of some hairs and paraphyses (e.g. in Melzer) but I do not know if it is common in dry samples.
Older apothecia became brownish after drying, and hymenium is quite dark in some cases. Only very young sporocarps are whitish even when dry.
Thank you for nice drawings.

Your observations are correct. When you study dry samples the spores are dead after some time (sometimes only after several months or years). Then the spore and ascus size does not change in MLZ.

But please use IKI for the apical ring because of the red reaction in some species.

The VB-guttules (vacuolar, not lipidic) in the living state are impossible to trace in herbarium material in Lachnum. Any granules you see in dried samples rehydrated in water or MLZ are of different origin and taxonomically useless.

The VBs induce the red-brown colour change in the dry or senescent state. Young apothecia when cautiously dried best keep the whitish original colour.

Zotto