Parmotrema reticulatum

Always seem to struggle with foliose lichen so the best way to get good at them is to keep trying. First clues were with UV and chemical tests. There was a faint UV+ purple, C- and K+ yellow turning red. Visually the upper surface showed many fine cracks showing the white medulla and the underside was mainly black with brown lobe tips. The rhizines present are simple and fading towards the lobe margins but the lobe tips had some sparse simple rhizines. Overall this was enough information to key out this foliose lichen to Parmotrema reticulatum.

Parmotrema reticulatum underside of lobe

Parmotrema reticulatum upper side of lobe

Fuscidea lightfootii

Found this morning on a wooden gate. Only a single simple spore was found with 1µm epispore measuring 10x7.5µm not enough to to be certain of identity. If this was a typical spore then Lecidella elaeochroma f soralifera a contender but tests show it to be something else. The thallus was UV+ white and C- suggesting something more like perhaps Fuscidea lightfootii. However, when performing a second section on a younger looking apothecia I found multiple dumbel shaped spores which were typical of Fuscidea lightfootii measuring 8x3.5µm

Fuscidea lightfootii

Rhizocarpon lavatum?

It doesn't take much effort to determine a Rhizocarpon but getting to species level is a lot more difficult. This one wouldn't key out so I instead went with the closest match. No idea what the difference between muriform, submuriform and eumuriform is and no explanation in the book. Perhaps it would have been easier to reach an ID had I have known. I've put the details here to come back in time and re-evaluate:

Spores: muriform (or could be submuriform or eumuriform) 25x11.25µm turning brown when mature.
Ascus: 120µm
hypothecium: brown
hymenium: colourless
epithecium: brown
apothecia: 0.8mm
habitat: siliceous rocks near stream

Pos Rhizocarpon lavatum

Caloplaca from Brecon Beacons 25th March

Found on 25th March 2016 on a gate post this Caloplaca was not found to be identifiable with my level of expertise currently. A shortlist was drawn up using apothecia size (1mm) and habitat giving Caloplaca citrina as the best guess. Both the thallus and apothecia are K+ purple eliminating C. virescens and C.cerina. Apothecia colour elimnated herbidella. There were few polaricula spores the largest measured 15x4.5µm. Some of the paraphyses had swollen tips measuring 3.75µm

Lecanora pulicaris

Lecanorine apothecia up to 1mm
Thallus white crustose K+ yellow
Spores 15x7µm simple
Fine crystals extending from the epithecium into the hymenium seen with a polarizing filter.
Massive crystals in the exciple.

Lecanora pulicaris

Opegrapha sp. (vulgata)?

I've had to put this lichen down as Opegrapha sp. as it doesn't key out. I've put the information here so it can be referenced in the future should I get more information regarding missing species in current literature. Closest match would be O.vulgata but what looks like pycnidia is in fact the early stages of new lirellate.

Lirellate 1mm
Thallus endolithic with a greenish tint
No pycnidia, only newly formed lirellate resembling pycnidia.

Spores 5-septate 22x5µm
Ascus 42x12µm

Generic Key 5 p.57
True exciple present
Ascospore septate
Ascospore multiseptate
Ascospore lumina cuboid
Ascospore colourless
Lateral exciple in section brown-black
= Opegrapha or Lecanographa

Opegrapha key:
Photobiont present (not lichenicolous)
Thallus without soredia, apothecia present
Ascospore 5-septate
Apothecia disc remaining slit like
Ascospore 4-7 septate
On bark
Ascospore 4-9µm wide
Key end, no match.

Opegrapha's characteristics:
O.anomea - On Pertusaria amara
O.areniseda - Mainly coastal on soil and sand
O.atra - Clearly defined mosaic forming patches
O.brevis - On Thelotrema petractoides
O.calcarea - On rock
O.cesareensis - Coastal siliceous rocks
O.corticola - Sterile
O.demutata - White pruina
O.dolomitica - On calcareous schists
O.fumosa - Sterile
O.glaucomaria - On Lecanora rupicola
O.gyrocarpa - On siliceous rock
O.herbarum - Slit opening wide when mature
O.mougeotii - Limestone, mortar, calcareous sandstone
O.multipuncta - On small branches
O.niveoatra - Often sterile
O.ochrocheila - K+ magenta-red
O.parastica - On Aspicilia calcarea
O.paraxanthodes - Mainly upland deeply shaded rocks
O.pertusariicola - On Pertusaria leioplaca
O.physciaria - On Xanthoria parietina
O.prosodea - 50-70µm ascospores
O.pulvinata - On Dermatocarpon miniatum
O.rotunda - On Physconia distorta
O.rufescens - Apothecia .3 to .5mm
O.rupestris - On V.baldensis
O.saxigena - Deeply shaded siliceous rock
O.sorediifera - Sterile
O.sphaerophoricola - On Sphaerophorus globosus
O.subelevata - On limestone, mortar and sandstone
O.thelotrematis - On Thelotrema lepadinum
O.trochodes - Apothecia 0.15-0.4mm
O.varia -
O.vermicellifera - Similar to Lecanactis subabietina
O.viridis -
O.vulgata -
O.xerica -
O.zonata - Shaded siliceous rocks
O.zwackhii - On Phlyctis argena

Caloplaca citrina

1. Caloplaca saxicola
2. Diploicia canescens

No. 3
Thallus crustose-areolate
On basic rock
Thallus K+ purple

Again the K+ purple led to a Caloplaca species:

Thallus entirely sorediate
Thallus without any definite shape or form to the margins (see C.xantholyta)
Thallus yellow-green with distinct areoles often sparsely fertile

Caloplaca citrina