Lobaria pulmonaria

If you're into woodlands, but not lichens, as I'm deeply ashamed to say that not so long ago I was, then the first lichen to grab your attention might well be Lobaria pulmonaria, tree lungwort.

It's big. It's extravagant. It has even got a catchy name.

I'd like to say, I liked tree lungwort before it was cool. But that would be (as is normally the case when people use that line of argument) complete nonsense. All the same, for me, like so many others, Lobaria pulmonaria was a serious gateway lichen...

Lobaria pulmonaria is one of four lobarion lichens present in the UK - though the three others have now been assigned to different genera. The primary habitat of all four is in ancient woodland on trees with less acidic bark, such as hazel, ash and mature oaks. All four species are sensitive to the acidifying effects of sulphur dioxide air pollution and have seen large contractions in range since the industrial revolution.

Lobaria pulmonaria is perhaps the least oceanic of the Lobaria species, having previously been widespread in the East. However, as an ancient woodland species, it is slow to recolonise areas where it has been lost (Dobson, p.275) and outside of Scotland, things are so dire that translocations have been attempted.

As you can see in the image at the top, it's still doing pretty darn well in parts of Argyll. Around here, it occurs on young hazel, old oaks, live ash, dead ash... in well-lit places within woodlands, it is so profusive that you might think twice before hanging your clothes on the washing line (should you have a washing line is such a place), less they become substrate for a lichen for which Scotland has international responsibility.

Tree lungwort has even managed to colonise four of the indicator species lists for high quality lichen assemblages recognised by Sanderson et al. (2018): the Southern Oceanic Woodlands Index (SOWI), the Suboceanic Woodland Index (SWI), the Boreal Woodland Index (BWI) and the Maritime Rock and Coastal Slope Index (MRCSI). It is not listed on the Lowland Rainforest Index (LRI) or Upland Rainforest Index (URI), presumably because it is so abundant in these areas.

In his invaluable lichens guide, Frank Dobson describes the apothecia (fruiting bodies) of Lobaria pulmonaria as "fairly rare", but I have seen plenty of them this year. Those are the orangey disks in the photo below. These are lecanorine, meaning their edges are made up of the same stuff as the rest of the lichen - a combination of both algal and fungal cells.

Tree lungwort is pretty distinctive once you've seen it a few times - no other lobarion species has ridged lobes. Perhaps, the most likely species to confuse it with is the more oceanic (and less bushy) Ricasolia virens (previously Lobaria virens) - fear not, a blog post on this is soon to follow.