Mark Powell

I had always wondered how traditional wells were dug and what the aquifer is that is about 14 feet deep in my lane (the stable water level of several local wells). I had guessed it was a bed of fractured limestone, I was wrong.

A single Home Counties gravestone: 31 lichen spp. and 2 lichenic. fungi. Calcareous sandstone so a rich mixture of species straddling the acid/basic divide. Superb colony of Bacidia rubella (much more common on gravestones than on trees around here).

One English gravestone, ten years experience, ten minutes examination, 23 species of lichen (three of which will require checking microscopically). To many people's surprise, Pyrrhospora quernea is much more common on gravestones than on trees in E. England

A thread about the lichenicolous fungus Laetisaria lichenicola, including the surprising way it was added to the British list in 2015 and hints about identifying/recording it.

During my early microscope investigations, I noticed two features of C. chalybeia not mentioned in the books. The rounded hyphae of the hypothecium are somewhat distinctive. At the time I first saw the pale patches on the photobiont cells, I had no idea they were haustoria.

Catillaria chalybeia in section. Some individuals lack the dark green pigment and then they may be confused with the var. chloropoliza which is a different sort of thing occurring in more specialised habitat.

William Borrer's description of the thallus of Catillaria chalybeia, written in the 1830s, captures its appearance better perhaps than any other account that I have seen.

West and East facing sides of the limestone gravestone to Mercy Ann Smith, died 1911. The latest stone to be scrutinised in detail. 24 lichen spp. present, over a third of which would have been unrecognised or likely misinterpreted at the start of this century. Thread

I found a technique to make reasonably good drawings, initially of microscopic features, but it works for anything that can be shown on a laptop screen. There are however some advantages to drawing freehand... Thread.

My favourite type of 'art' is an annotated drawing (even if just a rough sketch), a pleasing visual summary of someone’s careful observations.

The Lichen Flora of Great Britain, Ireland and the Channel Islands Rev. W. A. Leighton (1879) C and K were already in use at this stage. Many of Leighton's comments still seem apposite today. Thread

I recommend practising the K/UV reactions before using them to aid identification. L. elaeochroma (K/UV+ pale green when wet) on the left. L. hybocarpa (K/UV+ yellow developing as the spot dries) on the right. Thread

Fuscidea lightfootii, the first image showing two different morphs and the second demonstrating the intense white fluorescence of the medulla. Why do I post about F. lightfootii today? Thread.

An amenity sycamore tree with abundant Physcia adscendens and Xanthoria parietina. Hardly worth looking at? Well, it supports some nice examples of a lichen described as new to science in 1999. A thread about Lecanora compallens.

Lecanora compallens, close up of edges, the first showing a typical narrow zone of minute thalline warts. The second image shows an edge where soredia extend to the margin, obscuring any thalline warts.

It suddenly dawned on me just how useful UV torches and the 'new' K/UV tests have become during fieldwork. Thread, containing some examples of common identification issues which are now more easily resolved in the field.

Weddellomyces epicallopisma has almost completely killed its host in some patches.

First for a couple of well known and uncontroversial lichens, both Caloplaca (despite appearances). C. flavescens and C. teicholyta.