Bacidina?

[RobYaxley]

Found on the upper surface of an old Blushing Bracket in secondary birch/ oak woodland at East Winch Common SSSI in west Norfolk. A pale thin thallus with fine green granules, I’m assuming these are goniocysts. Amongst them were white pycnidia, bearing narrow hooked/ curled conidia up to maybe 40um, though the curl makes this difficult to judge. My working assumption is Bacidina sp, and I don’t know if it can be taken any further, or could it be something else? No apothecia present.

[Mark Powell]

I think the conidia being strongly hooked at least at one end is quite diagnostic for Bacidina modesta or at least that is what we used to think when we called it B. sulphurella. It would be interesting to hear from anyone who can confirm or dispute my assertion that a lichen such as yours, with a thallus composed of small goniocysts and with pale pycnidia containing filiform, strongly hooked conidia, can be reasonably named as B. modesta even without apothecia.

There was a time, perhaps between ten and fifteen years ago, when I seemed to find B. ‘sulphurella’ quite commonly on shaded bark but it seems to have become rather scarce now in my region. This follows the pattern of so many lichens, which seem to have a sort of heyday at certain periods during our changing atmospheric pollution regimes. I can well imagine B. modesta growing on the remains of an old bracket fungus so the substratum doesn’t cause me any concern.

[RobYaxley]

Thanks Mark, wasn’t on my radar at all! The LGBI3 key relies on presence of apothecia for the couplets before this species is arrived at, so any attempt at keying would have had to involve a guessing game. But having read the description that does look right. A county / vice county first I believe. Rob

[Neil Sanderson]

Yes agreed

Also in LBG2 Sterile Crustose Key 7e keys out Bacidina modesta:

[attachment=0]Screenshot 2026-01-21 at 19.00.01 copy.png[/attachment]

The LGBI3 editoral team will need to update these, so may need to add some species, but keying out Bacidina with pyncidia should be doable

Neil

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