ASCOMYCOTA | LECANOROMYCETES > LECANORALES > Lecanoracea

Genus Lecanora, meaning 'beautiful small bowl' - from the shape of the apothecia

Common name:            Members of the genus collectively known as 'rim lichens'

Synonym:                    Some former species now listed in the genera Myriloecis or Glaucomaria 

Primary habitat:            Woodland, parkland, wayside trees, coppices etc  

Usual substrata:            Bark - trunk, branches and/or twigs

Growth forms:              Corticolous  

Thallus:                  Crustose

Apothecia:                    Lecanorine

BLS identity rating:        Graded from 2/5 to 4/5 dependent on the species

Introduction

Leconora is a large, difficult genus with around sixty described species that occur in many different habitats on a wide range of substrata.

For this particular section I'm only interested in the corticolous species that may be found locally.

In many cases they cannot be reliably identified from photos, but that shouldn't put off a general observer's keenness to learn and, where possible, trying to come up with the most likely candidate for the different specimens photographed.

That said, it's rather daunting, so to start with its useful to have a list.

The most common species that I'm going to encounter are in the Lecanora subfusca group. I'm not sure exactly how many different forms are allocated to this group, but there are five that I particularly need to consider: Lecanora chlarotera, L.holocarpa, L.argentata, L.pulicaris, and L.sinuosa. For me, they are the most important and are discussed separately on the next page.

But, I also need to be aware of:

Leconora horiza: a local species that may be found on the bark of deciduous trees, especially mature Ash (Fraxinus), Elm (Ulmus) and Maple (Acer); and Lecanora intumescens: a widespread, but unfortunately rather scarce, lichen found on smooth-barked deciduous trees.

Next, there are two not dissimilar species with apothecia heavily covered in white pruinose: Lecanora albella and L.carpinea, although the latter has now been renamed Glaucomaria to confuse matters. I believe that I've photographed that species, so there's a dedicated page providing full details.

Others that I may encounter, in a vague order of interest, are:

L.jamesii: apparently frequent towards the base of sheltered smooth-barked trees, often occurring on Willow (Salix) in damp situations; rarely fertile; primarily a western species but recorded locally. L.confusa: more abundant near the coast where it can be found on deciduous trees and shrubs, particularly on small branches, twigs and stems. L.conizaeoides: on trunks of old Birches, and Pine twigs; used to be common, but is now becoming rarer. L.symmicta: a species that occurs on acid barked, mainly coniferous, trees, such as Pine.

Then four where the thallus is more of a rarely fertile continuous sorediate crust: L.alboflavida, L.barkmaniana, L.compallens and L.expallens.

That's a maximum of 17 species, but that can be made up to a round 20 by including three that were former Lecanora species, but now in the genus Myriloecis. They are M.dispersa, widespread and common in the countryside on nutrient-rich bark, and M.hagenii and M.persimilis, two rather similar species found mainly on twigs, the former favouring softer-barked trees, such as Elder (Sambucus) and Poplar (Populus).

It should be remembered this page only refers to corticolous species occurring on the bark of live trees. There are a couple of other Lecanora species that can be found on weathered timber, but not trees, that will be featured in this section if I find them. Additionally, it should be noted that some of the species mentioned above may also occur on other substrata, such as rock and stonework.