Apothecia are up to 3 mm diameter with a short stalk; the hymenium is pale brown with a darker margin.

Excipulum is a textura oblita in part, with thin-walled cells in part.

Asci are 85-100 x 10 µm, with tips staining blue in IKI. Spores are single-celled, 12-14 x 4.5-5 µm, with 2 large oil bodies and many minute oil bodies.

Paraphyses are 3-4 µm wide, with oil-filled contents in the upper part.

The colour of the apothecium and other characters would appear to rule out Rutstroemia (Lanzia) luteovirescens, which is characteristic of Acer. Microscopic characters don't seem to fit well with other species found on decaying tree leaves, so I'm struggling to make an identification.

I would be grateful for any help.

Marcus

Hans-Otto Baral, 27-10-2013 22:08

Re : Rutstroemia on Acer campestre leaves

Hi Marcus

this is Rutstroemia "kalevi".  You find it in folder Rutstroemia.

The name might be a creation by the late Terry Palmer, but I do not remember the etymology.

An undescribed species, though perhaps hidden under some old name, who knows.

Apparently very rare!

Zotto