Peltigera polydactyla ?

[kiltoncomp]

There were masses of these growing on mossy areas in damp young woodland, at Rother Valley Country park today, i have narrowed it down to its being Peltigera polydactyla , but confirmation would be great,
for a place that is reclaimed land and still young, there is a suprising variety of lichens around the park, albeit the more common ones, but still interesting finds



thanks,
Brian.

[JennyS]

Hi Brian - did you consider Peltigera hymenina as that seems more likely?
Peltigera hymenina (images of British lichens)

P. polydactyla should have darkish brown veins and rhizines on the underside and small lobules on the lobe margins

[kiltoncomp]

Originally Posted by JennyS

Hi Brian - did you consider Peltigera hymenina as that seems more likely?
Peltigera hymenina (images of British lichens)

P. polydactyla should have darkish brown veins and rhizines on the underside and small lobules on the lobe margins

Hi Jenny,
i think your suggestion is much nearer the mark, especially now i have had a better look at the underside of it,


as you can see by the (not to good) picture, the veins are more of a dirty yellow, rather than the dark brown as P.polydactyla has,

the upper surface is more of a dark green than appears in the pictures
so all in all i would say you are most likely spot on with your suggestion

many thanks,
Brian.

[AlanS]

I agree that this is Peltigera hymenina. The pale ochre veins are diagnostic and though the old rhizines are shown as dark brown, we can also see in the first photographs that they are pale when fresh.

P. polydactylon (correct spelling under current rules, contrary to several books) is rare in Britain and the great majority of past records here refer to P. hymenina. I have seen it only once, in a grassy basalt quarry near me, from which I fear it may now have disappeared. The veins on the underside are conspicuously dark. My impression of it, reinforced by authentic photographs from the continent, is that the apothecia are held more rigidly erect and really do look like "many fingers" as the name suggests.

Alan

[kiltoncomp]

many thanks Alan,
P.hymenina is not in one of my two lichen books and in the other "lichens - Frank Dobson" it is listed together with P.polydactyla, as having the same features, i think the fact that it is a 1979 issue may have some bearing on my confused id
the rhizines were almost white on the younger portions, being darker on the older parts , especially where they were in contact with the ground,


Brian.

Originally Posted by AlanS

I agree that this is Peltigera hymenina. The pale ochre veins are diagnostic and though the old rhizines are shown as dark brown, we can also see in the first photographs that they are pale when fresh.

P. polydactylon (correct spelling under current rules, contrary to several books) is rare in Britain and the great majority of past records here refer to P. hymenina. I have seen it only once, in a grassy basalt quarry near me, from which I fear it may now have disappeared. The veins on the underside are conspicuously dark. My impression of it, reinforced by authentic photographs from the continent, is that the apothecia are held more rigidly erect and really do look like "many fingers" as the name suggests.

Alan

[AlanS]

Originally Posted by kiltoncomp

many thanks Alan,
P.hymenina is not in one of my two lichen books and in the other "lichens - Frank Dobson" it is listed together with P.polydactyla, as having the same features, i think the fact that it is a 1979 issue may have some bearing on my confused id
Brian.

Ah, yes, 1979 would be the original 'Dobson', and we are now on the 2005 5th edition - many more species, colour photographs, distribution maps, modern names - a superb book. (So good that I just bought myself another copy, as my working copy is getting so battered.)

Now we also have the new, reasonably definitive (at this moment in time) The Lichens of Great Britian and Ireland edited by Smith et al. (1046 pages of technical description, no photographs, few line drawings) published a couple of months ago with various new names, it may be that there will be yet another edition of Dobson in due course. I haven't heard anything but it seems possible.

Anyhow, our understanding of Peltigera has improved much in recent years. A Finn, Orvo Vitikainen, published a really excellent revision of European species in 1994 and that marks a watershed in Peltigera identification. Prior to that time, P. hymenina was indeed likely to be called "polydactyla", before the distinction of the species was understood. Another name that was in use for what we now know as P. hymenina was "lactucifolia" (a confused name of uncertain application).

So, with your books, you were right - but P. hymenina is now the name for our commonest species. (And, to be honest, it is still a difficult genus and even 2005 Dobson is rather limited in this case.)

Alan