Search found 47 matches

by Mark Powell
Thu Feb 07, 2019 6:24 pm
Forum: Lichens
Topic: Opegrapha atra
Replies: 12
Views: 3245

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: 1501

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
by Mark Powell
Mon Feb 04, 2019 10:02 am
Forum: Lichens
Topic: Pd/UV Spot Tests
Replies: 4
Views: 1501

Re: Pd/UV Spot Tests

Hi Neil, Many thanks for these observations. I haven't got far with investigating Pd/UV reactions except to notice, as you have done, that sometimes a bright fluorescence is seen. This is not the Pd fluorescing (in case anybody wondered) because Pd on an inert, non-fluorescent surface gives a weak m...
by Mark Powell
Fri Feb 01, 2019 10:45 am
Forum: Lichens
Topic: Muellerella lichenicola
Replies: 1
Views: 768

Re: Muellerella lichenicola

I can't give you a definite yes or no for M. lichenicola but I suspect that specimens like yours, in calcareous communities and with numerous brown, septate ascospores in the ascus, would often be named as M. lichenicola. One wonders whether there are several cryptic taxa involved. I once had a hypo...
by Mark Powell
Mon Jan 28, 2019 10:53 pm
Forum: Lichens
Topic: Phaeographis smithii?
Replies: 6
Views: 2013

Re: Phaeographis smithii?

*bluddy* great to see Brian on here. Yes, P. smithii is turning up with some frequency in the east now. The very talented Lewis first sent me a specimen of this from an orchard near Wisbech (?2013) when it seemed like a crazy exotic. Since then, in the past five years or so, we have found P. smithii...
by Mark Powell
Fri Jan 25, 2019 4:56 pm
Forum: Lichens
Topic: Xanthoria
Replies: 14
Views: 4449

Re: Xanthoria

Hi Chris, That's a really kind offer. You wouldn't necessarily need to send the whole pebble. You could just scrape a bit of the 'infected' Caloplaca off into a packet if that makes it easier/cheaper for you. It would interest me to compare the Monodictys microscopically with cyanobacterial cells fr...
by Mark Powell
Fri Jan 25, 2019 12:08 pm
Forum: Lichens
Topic: Abrothallus on Melanohalea exasperata
Replies: 5
Views: 1648

Re: Abrothallus on Melanohalea exasperata

The recommended way to submit records of unknowns or tentative identifications to the BLS database is to put just the genus in the 'Species' column (column J) and then to put a short description in the 'Record Notes' column (column R). For a lichenicolous fungus the host can be put in the small scal...
by Mark Powell
Wed Jan 23, 2019 4:47 pm
Forum: Lichens
Topic: Xanthoria
Replies: 14
Views: 4449

Re: Xanthoria

This has been a fascinating subject for me so I am glad that you posted about your 'last pebble'. I don't know any lichenologists who do spore drops but we might get better results if we did... I have ever known lichenologists to measure spores in squash preparations, measuring the ones released fro...
by Mark Powell
Wed Jan 23, 2019 9:48 am
Forum: Lichens
Topic: Xanthoria
Replies: 14
Views: 4449

Re: Xanthoria

I think those ascospores are fine for Caloplaca . They are septate, with a broad septum. If you are looking at images in books, bear in mind that the published images will be of 'cleared' spores. Your micrograph shows spores that appear to be fresh and mounted in water and hence the cell contents pa...
by Mark Powell
Sun Jan 20, 2019 9:27 am
Forum: Lichens
Topic: A new lichen for GBI?
Replies: 14
Views: 3961

Re: A new lichen for GBI?

Chris, I don't know how easy it is to acquire Nimis & Martello but it is all in English. I have only seen the terricolous version which I rate highly. The introductory sections are good, starting with three pages of discussion about what 'terricolous' really means (which I found fascinating). This w...
by Mark Powell
Sat Jan 19, 2019 7:05 pm
Forum: Lichens
Topic: A new lichen for GBI?
Replies: 14
Views: 3961

Re: A new lichen for GBI?

Hi Paul, This reply is mainly to say that I too am following with interest. It is also a first attempt at posting (and in relative ignorance of squamulose terrestrial things). The spores in your putative Placidiopsis cinereoides look as though they are truly septate (even if they are late forming th...