Thursday 31 December 2020

Chapel le Dale - Peltigera horizontalis and Peltigera praetextata

 Not all Dog Lichens are the same.

A delightful pre New Year walk with Doris Cairns along a road / track through a mossy wood / limestone pavement, near Chapel le Dale, with moss covered walls and pavement reveals two new ones on 30 December

My natural reaction to a big Dog Lichen is "It must be Peltigera membranacea" - especially as the two we find today both have a thallus that was not flat, but slightly  buckled / rugose / or using the the technical term,  bullate.

Both are growing straggling over moss growing over limestone rocks and a limestone wall - and in an area that must be sheltered and moist by the amount of moss growing on the trees and rocks. 

Both look magical with frost crystals twinkling round the margin of the thallus.

They are Peltigera horizontalis and Peltigera praetextata

1. Peltigera horizontalis













Inspection of the under surface that evening shows
The rhizines are brushlike (Dobson says rope like)
The rhizines are dark brown
The rhizines are arranged in concentric rings
The undersurface is pale at the margin and pale between the dark veins








The trunk of an oak tree near a cattle grid has some Pertusaria pertusa growing on it






2. Peltigera praetextata

"P praetextata has grey  brown,  often dense, scale like isidia along the margins and on any cracks on the thallus"




The rhizines in Peltigera praetextata are relatively simply. They are not branched and not like brushes.











Homeward bound











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