Clare Island Survey — Lichenes. 14 3 



profusion : one patch 14 inches in length forming " a crimson band of exquisite 

 beauty, owing to the vast amount of fructifying podetia." 



Early in October, 1910, accompanied by Miss Knowles, Mr. Praeger, and 

 other botanists, I visited Achill Sound, Clare Island, Louisburgh, Belclare, 

 Westport, and Castlebar. We explored generally the whole district, and 

 made large collections, which were, as before, determined at South Kensington ; 

 and I have again to thank Miss Knowles for her assistance in the arduous 

 task of examining the specimens with the microscope. We had many 

 duplicates sent in by the different workers and from the different localities, 

 but finally we were able to reckon about 280 species with forty sub-species, 

 varieties, or forms. Of these, according to Mr. Adams's " Distribution of 

 Lichens in Ireland," 1 only about thirty had been previously recorded in 

 the sub-province marked by him C2 (the County of Mayo) in which our district 

 is included. A large number had been already collected in Gal way, but 

 between thirty and forty on our lists are new to Ireland. There are nine in 

 Mr. Adams's list recorded from Mayo that we did not find. These are : — 

 Bacidia effusa {intermedia) Arm, B. luteola (rubella) Mudd., Bicellia advenula 

 A.L.Sm., Collema fiaccidum Ach., Gyrophora erosa Ach. (?), Zecanora pyracea 

 Nyl., Zecidea arridens Nyl. (?), Porina lectissima A. Zahlbr., and Boccella 

 fuciformis, DC. 



As has been already stated, a region of rock, moorland, and sea-coast such 

 as that selected by the Clare Island Committee for their survey is peculiarly 

 favourable for the development of an abundant lichen flora. These lowly 

 plants are mostly of slow, continuous growth, the same plants and even the 

 same fruits persisting year after year ; so they flourish best on some 

 substratum that is not subject to change or disturbance. The number of 

 species on our list gives but little idea of the vast lichen growths that are to 

 be found on the western shores. The exposed rocks were everywhere covered 

 with sheets of leafy Parmeliae or densely coated with mingling crustaceous 

 forms which competed for every inch of space, while the peaty soil yielded 

 fine growths of Cladonia and Stereocaulon, and spreading over the grass 

 were various species of Peltigera, notably P. canina and P. rufcscens, with its 

 crested form praetextata. 



The rocks bordering the sea and the great cliffs of the north-west shore of 

 Clare Island are black with an unbroken growth of Vemicaria maura, 

 IAchina pygmaea, a small, dark, shrubby lichen, is also abundant on some of 

 the rocks washed by high tides ; and within reach of the spray Bamalina 

 scopidorum and B. cu&pidata found room for their grey tufts of strap-shaped 



1 Proc. E. I. Acad., xxvii., Sect. B., No. 10. 1909. 



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