Search found 21 matches

by Mark Powell
Sun Jun 16, 2019 6:11 pm
Forum: Lichens
Topic: Opegrapha rupestris on Thelidium decipiens
Replies: 2
Views: 498

Re: Opegrapha rupestris on Thelidium decipiens

Hi Juliet, The host would make Opegrapha hochstetteri ined. more likely (Thelidium decipiens being probably closely related to Verrucaria hochstetteri). The draft lichenic. key doesn't have a couplet which includes O. hochstetteri (this species is just treated with a brief footnote). The couplet whi...
by Mark Powell
Tue Mar 05, 2019 9:37 am
Forum: Lichens
Topic: Help!
Replies: 3
Views: 727

Re: Help!

I had the same reaction as Neil. The brown surface with cracks shows some superficial similarity to the upper surface of some Peltigera species but I think this is probably a non-lichenized fungus. I always carry a razor blade in the field and one of the uses for this is to check for any photobiont ...
by Mark Powell
Mon Feb 25, 2019 11:38 am
Forum: Lichens
Topic: Lecidella elaeochroma anamorph?
Replies: 2
Views: 568

Re: Lecidella elaeochroma anamorph?

Yes, I feel sure that you have the anamorph of the L. elaeochroma there. The pigment in the pycnidial wall is correct (blue-green) along with the thin, curved conidia. Here are some images of one of my specimens. In this case the pycnidium is not as immersed in the thallus as yours because mine was ...
by Mark Powell
Mon Feb 25, 2019 8:47 am
Forum: Lichens
Topic: Parmotrema on hazel
Replies: 3
Views: 695

Re: Parmotrema on hazel

I collected a bit of P. perlatum yesterday. I don't observe a bright blue fluorescence of the medulla in my specimen using the Convoy S2. I do see an off-white reflectance that looks pale compared with the dull, mauve-brown of the cortex under UV. This reflectance is, if anything towards the yellow ...
by Mark Powell
Mon Feb 18, 2019 10:30 am
Forum: Lichens
Topic: Lichenicolous fungus on Xanthoparmelia mougeotii
Replies: 4
Views: 748

Re: Lichenicolous fungus on Xanthoparmelia mougeotii

The ascospores of the fungus on X. mougeotii seem rather different in structure compared to 'Pyrenidium actinellum' on e.g. Caloplaca teicholyta. Those of 'Pyrenidium actinellum' remind me of those in Pyrenula with an unevenly thickened wall. The first photograph shows the ascospores of the fungus o...
by Mark Powell
Mon Feb 18, 2019 9:03 am
Forum: Lichens
Topic: Lichenicolous fungus on Xanthoparmelia mougeotii
Replies: 4
Views: 748

Re: Lichenicolous fungus on Xanthoparmelia mougeotii

Hi Heather, This is a coincidence because I am sure this is the same fungus that I found infecting X. mougeotii recently in a churchyard in Hertfordshire. I haven't got around to studying it properly yet. The closest thing in the draft lichenic. keys seems to be Pyrenidium actinellum and this has be...
by Mark Powell
Mon Feb 11, 2019 11:34 am
Forum: Lichens
Topic: Athallia (Caloplaca) pyracea?
Replies: 5
Views: 870

Re: Athallia (Caloplaca) pyracea?

Hi Juliet, I agree with all your comments about these corticolous Caloplaca species. C. pyracea does stand out as something different. I check quite a few C. 'cerinella' specimens and find they ARE almost invariably C. cerinella. I very occasionally come across 8-spored Caloplaca on smooth bark and ...
by Mark Powell
Mon Feb 11, 2019 8:58 am
Forum: Lichens
Topic: Athallia (Caloplaca) pyracea?
Replies: 5
Views: 870

Re: Athallia (Caloplaca) pyracea?

I agree that it looks fine for C. pyracea. It has the definite grey thalline margin which then often becomes rather excluded as the apothecium matures. My decision is based much more on gross morphology than any microscopic characters. It is turning up quite regularly in my part of the world, most c...
by Mark Powell
Sat Feb 09, 2019 8:02 am
Forum: Lichens
Topic: Phylloblastia
Replies: 7
Views: 1148

Re: Phylloblastia

I haven't seen Phylloblastia cf. bielczykiae further north than Epping Forest. This is in contrast to the other two Phylloblastia species. I found P. fortuita in N.E. Yorkshire and P. inexpectata extends up into Scotland. Just a note on filling in spreadsheets, I thought that we were discouraged fro...
by Mark Powell
Fri Feb 08, 2019 8:04 am
Forum: Lichens
Topic: Opegrapha atra
Replies: 12
Views: 1625

Re: Opegrapha atra

Hi Chris, I have sent you a message with my email address. I will be happy to send you the spreadsheet with the lichenicolous records in the BLS database (as of about a year ago). I had hoped that this would be made available as a download on the BLS website (along with a 'health warning' as there a...
by Mark Powell
Thu Feb 07, 2019 6:24 pm
Forum: Lichens
Topic: Opegrapha atra
Replies: 12
Views: 1625

Re: Opegrapha atra

Hi Chris, I really must try this spore-drop technique... However, there may be reasons why lichenologists haven't traditionally used spore-drops. We often examine herbarium material and I presume that spore-drops only work with fresh specimens. If we started to use spore-drops with fresh material an...
by Mark Powell
Tue Feb 05, 2019 8:46 am
Forum: Lichens
Topic: Pd/UV Spot Tests
Replies: 4
Views: 833

Re: Pd/UV Spot Tests

On the subject of UV tests, I have been asked by several people about effective eye protection. The cheap glasses I bought didn't work. Do you have make and model of the ones you use handy?
Thanks,
Mark