Knowles — The Maritime and Marine Lichens of Hoivth. 125 



Ph. stellaris Nyl. 



fvai-. leptalea Nyl. — On rocks, associated witli Ph. parietina; frequent, 

 tvar. subobscura Nyl. — On shady rocks, Old Boat-house, with Ph. 

 parietina ; rare. 



subsp. tenella Nyl. — On rocks just above high-water mark. Bottle 

 Quay and Broad Strand; common. 

 tPh. aipolia Nyl. — On the sea-wall, Sutton ; frequent. 

 *Ph. tribacia Nyl. — On Blackthorns ; rare. 

 Ph. erosa Leight. — On rocks at the base of the cliffs, above high- water mark 

 Broad Strand ; frequent. 

 fPh. lithotea Nyl. — In depressions of rocks about high-water mark, Bottle 

 Q,uay, associated with Ph. tenella and Lecanora epixantha ; frequent. 



Tribe Lecano-Lecideei. 

 Sub-tribe Pannariei. 

 fPannularia nigra Nyl. subsp. psotina Cromb.— Sea-wall, Sutton ; rare. 



Sub-tribe Lecanorei. 



Lecanora (Squamaria) crassa Ach. — In crevices of rock on the shore between 



Lough Leven and High Iloom Bed ; rare. 

 Lecanora (Placodium) murorum Ach. — Eocks about high spring- tide level ; 

 chiefly in sheltered situations. 

 * subsp. decipiens Nyl. — On the Needles ; abundant. 



*subsp. tegularis Nyl. — Occasional on the south and south-west coasts, 

 but more frequent on the east coast, where it seems largely to 

 replace the species. It is very plentiful on the cliffs at Gaskin's 

 Leap. L. tegularis differs from L. murorum chiefly in its concave 

 apothecia and in the smaller size of the spores. Crombie describes 

 the margin of the apothecium of L. tegularis as entire. In the 

 Howth specimens it is crenulate or sub-orenulate, but as the 

 spores agree with Crombie's measurements (being 10-11^ x3-4^), 

 and as Nylander, in his original description of L. tegularis, says 

 nothing about the character of the margin of the apothecium, I 

 have placed the Howth specimens under this subspecies. 

 fL. (P.) callopisma Ach. — Seen only on the limestone at Balscadden Bay, 

 and on ttie Harbour wall ; rare. 



fsubsp. sympagea Nyl. — With the species ; rare. 

 fL. (P.) lobulata Somm. — Abundant all round the coast on rocks that are 

 washed by the waves at high spring-tides. 



