Search found 246 matches

by Mark Powell
Sat Apr 27, 2024 9:02 am
Forum: Lichens
Topic: Dorset, Anisomeridium viridescens?
Replies: 4
Views: 115

Re: Dorset, Anisomeridium viridescens?

I agree with Neil that the apparent presence of a distinct whitish thallus suggests that this isn't A. viridescens. Although we don't have a scale, judging by eye against the Physcia, this perhaps looks a bit chunky for A. polypori. I am going to tentatively suggest that you also consider A. biforme...
by Mark Powell
Fri Apr 19, 2024 10:30 am
Forum: Lichens
Topic: Lichen on Little Asby limestone
Replies: 8
Views: 169

Re: Lichen on Little Asby limestone

I meant to add that the rather strange appearance of the apothecia may be due to intense browsing, for example by molluscs.
by Mark Powell
Fri Apr 19, 2024 10:28 am
Forum: Lichens
Topic: Lichen on Little Asby limestone
Replies: 8
Views: 169

Re: Lichen on Little Asby limestone

I'm not going to provide a confirmed id at this stage but have you considered Aspicilia s. lat.? The ecology and apothecial pigmentation would fit, as would the fewer than 8 spores per ascus (in some species) and the rather large sub-spherical ascospores. Perhaps the biggest problem with my suggesti...
by Mark Powell
Mon Apr 08, 2024 8:57 am
Forum: Lichens
Topic: Protoblastenia lilacina?
Replies: 3
Views: 1725

Re: Protoblastenia lilacina?

I have encountered what I record as P. lilacina occasionally (rather rarely) on limestone memorials in Home Counties' churchyards. At first I was disconcerted by the lack of violet hypothecium in these specimens but such material certainly seemed significantly different to the much more common P. ru...
by Mark Powell
Mon Apr 08, 2024 8:24 am
Forum: Lichens
Topic: Crustose on Salix, not Lecania
Replies: 11
Views: 269

Re: Crustose on Salix, not Lecania

There isn't really a right or wrong answer as to whether this should be recorded as J. tavaresiana or not, it is perhaps more a matter of taxonomic judgement. People differ in their thresholds for recording a specimen as such and such. Looked at philosophically, the only specimens which are correctl...
by Mark Powell
Thu Mar 28, 2024 12:51 pm
Forum: Lichens
Topic: Possible Alyxoria viridipruinosa
Replies: 3
Views: 1800

Re: Possible Alyxoria viridipruinosa

The type description of Opegrapha viridipruinosa is available at the following link:https://www.mapress.com/phytotaxa/content/2011/f/pt00018p127.pdf Here are screenshots. Screenshot 2024-03-28 12.45.21 PM.png Screenshot 2024-03-28 12.45.40 PM.png Screenshot 2024-03-28 12.46.12 PM.png The distributio...
by Mark Powell
Thu Mar 28, 2024 12:37 pm
Forum: Lichens
Topic: Possible Alyxoria viridipruinosa
Replies: 3
Views: 1800

Re: Possible Alyxoria viridipruinosa

I find the distinction between A. varia and A. viridipruinosa a bit disconcerting. As so often in lichenology, I think it is best to consider a range of characters rather than to rely on just one or two. I always check the size of the conidia in making my decision as that seems to provide one of the...
by Mark Powell
Sun Mar 24, 2024 10:38 am
Forum: Lichens
Topic: A distinctive lichen with multi-spored asci. What on Earth is it?
Replies: 8
Views: 3214

Re: A distinctive lichen with multi-spored asci. What on Earth is it?

In Bedford Cemetery there are numerous calcareous sandstone gravestones from late Victorian and Edwardian times. These support an interesting intermediate community containing elements of the community on limestone and elements of the community on siliceous sandstone. Lecanora horiza is abundant on ...
by Mark Powell
Wed Feb 21, 2024 9:59 am
Forum: Lichens
Topic: Snowball lichen invading Arthonia thallus
Replies: 3
Views: 905

Re: Snowball lichen invading Arthonia thallus

It was also my first thought when looking at the 'snowballs' that they might well be the pruinose pycnidia of Opegrapha vermicellifera , forming little patches among the other ' Opegrapha ' with lirellae. To add to Neil's suggestions for the latter, we get a lot of Alyxoria ochrocheila in my region ...
by Mark Powell
Thu Feb 15, 2024 8:49 am
Forum: Lichens
Topic: Lecanora sulphurea vs Diploschistes caesioplumbeus
Replies: 1
Views: 841

Re: Lecanora sulphurea vs Diploschistes caesioplumbeus

In my local churchyards, Lecanora sulphurea grows in association with Tephromela atra on ironstone gravestones. I sometimes see small thalli of L. sulphurea apparently 'infecting' T. atra but I have never noticed the situation reversed (I haven't seen small patches of T. atra growing within L. sulph...
by Mark Powell
Wed Feb 14, 2024 1:30 pm
Forum: Lichens
Topic: Hyperphyscia lucida
Replies: 8
Views: 1944

Re: Hyperphyscia lucida

After collecting some of what I consider fairly typical H. adglutinata, I now feel more confident that my specimen from Bedford Cemetery really is H. lucida. I will post a couple of side-by-side images, then one of presumed H. adglutinata, and then a section of what I claim is a poorly developed pro...
by Mark Powell
Tue Feb 13, 2024 12:25 pm
Forum: Lichens
Topic: Hyperphyscia lucida
Replies: 8
Views: 1944

Re: Hyperphyscia lucida

I am pleased that this topic has been discussed on the forum. I previously found specimens which I thought resembled H. lucida but remained uncertain about them. Yesterday I found a particularly convincing colony, on the trunk of a large sycamore tree in Bedford Cemetery and it was this recent discu...