Holystone wood is noted for its lichen flora. The SSSI mentions a luxuriant community of epiphytic lichen including Bryoria and Usnea subfloridana. Many species are present which are associated with ancient woodland: Mycoblastus sanguineus, Thelotrema lepadinum and Pertusaria spp. The large oak shown above was a haven for Bryoria lichen. The tree in top left is covered in Usnea, Bryoria and Ramalina sp.
A close up the fruiticose Bryoria fuscescens on the large oak reveals its dark smoky-brown colours, and pendant, hair like filaments. It grows on acid barked trees.
Chrysothrix candelaris a leprose lichen formed a bright yellow/green splash on an oak tree.
Thelotrema lepadinum is another lichen with a Western and Northern distribution. The name lepadinum refers its limpet like appearance though it is also commonly known as the barnacle lichen.
This crustose lichen growing near the Thelotrema is Pertusaria pertusa. The same Beech tree also hosted P amara (a bitter tasting lichen) and P hymenea. Pertusaria corallina was abundant on rocks and walls.
Arthonia radiata has crowded black starry apothecia. Itis often found on smooth barked trees like Ash.
Mycoblastus sanguineus is a crustose lichen found on hard sandstone rocks. Could this be a specimen?
This crustose lichen, thickly covered in apothecia, looks like Lecanora gangaloides although I did not scratch it to reveal the orange colour underneath. Its lookalike Tephromela atra flourished further along the same wall.
Many species of crustose rock lichen such as Lecidea lithophila pictured above were abundant on the stones. Frequently red coloured from the deposition of iron oxides, L lithophila is common in the upland North and West.
It was surprising that so many of the lichen were fruiting, like this Lecanora rupicola above.
The apothecia shown above on this fruiting Parmelia saxatilis have orange-brown discs and isidiate margins.
Cladonia (cup lichen) also featured on this wall. The example above is the two pronged, Cladonia furcata.
Cladonia polydactyla seems to be ubiquitous in upland Northumberland. It has scarlet red fruits on its many fingers. The lichen with the thicker stalks is C sulphurina.
Lichens – Frank Dobson, BLS, 2018.