Lecania sylvestris

[PaulBowyer]

Hello,
I found this lichen on a south facing church wall in Weston-super-Mare today. With 1-septate spores I've have narrowed it down to Lecania sylvestris/hutchinsiae. I believe the substrate is more calcareous so would favour sylvestris but the thallus may perhaps be a little thick for this species favouring hutchinsiae. Does anyone have any thoughts on this specimen or know of any way to separate them with confidence?
Thanks,
Paul

[Neil Sanderson]

Paul

The LGBI3 has the following abandon all hope all yee who enter warning in the Lacania genus description

A notoriously difficult genus whose species tend to predominate in oceanic areas. Some of the species currently recognized can be very difficult to separate, particularly where thickness of the thallus or epinecral layer (dead cortical cells) are critical. Several saxicolous species, i.e. those in which the discussion centres on the occurrence on a specific type of rock, may turn out to be ecotypes of the same, polymorphic species; more comprehensive molecular studies would be useful.

Lecania sylvestris & L. hutchinsiae are described as closely related, which in Lecania is code for probably ecotypes of the same species, but more comprehensive molecular studies are required to prove this.

Your specimen does seem to have the thallus of L. hutchinsiae but is growing in L. sylvestris habitat. Certainly not typical L. hutchinsiae habitat of "on siliceous rocks, stones, scattered boulders, etc., often in moderate to deep shade, also in old woodlands or scrub". Best called Lecania hutchinsiae I suppose.

Neil

[PaulBowyer]

OK, many thanks Neil. Nice to have a second opinion. I've only seen hutchinsiae once and yet to find my first sylvestris.
Cheers,
Paul