Black apothecia on carstone

[RobYaxley]

From a site in NW Norfolk, in heathland. The pebbles here are an iron rich sandstone (carstone) and in places these can form small outcrops. These have some interesting species on (for East Anglia), including Trapelia glebulosa, Trapelia obtegens, Porpidia crustulata, Leimonis erratica and Porpidia soredizodes. This specimen I couldn’t place – black discs with no apparent thallus – convex with a thalline margin, deep green epithecium and paler green hymenium, no obvious colour in the hypothecium, 3-septate spores around 15um long. Haugania oederi seems to fit microscopically, but definitely doesn’t look like it. Any suggestions please.

[Neil Sanderson]

Rob

I was hoping someone more knowledgeable on rock would reply, but looking at the pictures and reading descriptions it looks like poorly developed Haugania oederi to me, presumably there because the sandstone is iron rich. An interesting addition to the lowland heathland pebble assemblage.

Neil

[Paul Cannon]

Scoliciosporum intrusum appears to tick most of the boxes, though it would be a big range extension…

Best wishes

Paul

[AlanFUSA]

Hi Rob (& Neil and Paul):

Apologies for my late response. I’m blocked from posting to this forum from my home network so have to wait until I go into the herbarium.

Haugania oederi and S. intrusum are both good suggestions but I don’t think it is either of those – H. oederi would have gyrose apothecia and a dark hypothecium, and I have only ever seen S. intrusum with 0–1-septate spores.

The apothecial section has the look of a Micarea and I rather suspect this is M. lignaria. Although that species usually has mutiseptate spores, it can also have 3-septate ones. I have collected such a specimen in Scotland and it had me fooled as well!

An alternative, left-field, suggestion would be a lichenicolous Arthonia in the hymenium of Lecidella stigmatea. It doesn’t look like A. intexta, but I’m sure there are others.

Cheers – Alan

[Author]

Posts