612 SUMMARY OF CURRENT RESEARCHES RELATING TU 



Lichens. 



(By A. LoRRAiN Smith.) 



Lichens of Arran.* — J. A. Whelclou and W. Gr. Travis publish an 

 account of lichens found bj them during a holiday on the island. 

 They also include many specimens collected by W. West and some pre- 

 vious workers. The field work was done mainly on the coast where 

 lichens are abundant and in fine condition. They note that a number 

 of species such as Verrucaria ni(/rescens, which are usually found on 

 calcareous rocks, grow on exposed spray-washed siliceous rocks on the 

 Arran coast. Various ecological notes are given, and a list of the 

 hundred and nineteen species is appended. 



Maritime and Marine Lichens of Howth-f — M. C. Knowles gives 

 a description of the geological and geographical features of Howth Head, 

 which forms the northern boundary of Dublin Bay. She also takes 

 note of the climatic and other conditions that affect the growth of 

 lichens in that region. She divides the coast into belts from low-tide 

 level upwards, and describes the types of lichen vegetation peculiar to 

 each area : " the composition of the rocks, and the amount of weather- 

 ing of the surface, have also a great influence on the abundance and 

 nature of the species." Ramalinse are very plentiful on the rocks, 

 R. scopulorum (including R. cuspidal a) being the most abundant. 

 Between the Ramalina belt and the sea, occurs the orange belt of 

 Physcia parietina, Placodium, etc., the more crustaceous P. lohidatum 

 coming lowest on the shore and sometimes sharing the rock with 

 Verrucaria mcmra. 



Terricolous lichens were not present in great abundance, but a fair 

 number of species were found. Corticolous species were scarce, as trees 

 were absent, and the only habitat ^as the blackthorn-scrub, or occa- 

 sionally whitethorn. On these were found species of Ramalina, 

 Evernia^ Parmelia, and Physcia, with a number of crustaceous forms, 

 They grew mostly in the forks of the branches or where the surface of 

 the branches was broken and somewhat roughened and cracked. The 

 list which follows contains 181 species, 13 sub-species, and 25 varieties. 

 Three species are new to science. 



Report on the Lichens of Epping' Forest. J — R. Paulson and P. 

 G. Thompson publish a second report on the Lichens of Epping Forest. 

 The first Ust included 46 plants, the present list adds 63, making a 

 total of 109 fully determined forms, which considerably exceeds the list 

 of 85 recorded by Crombie in 1883. 



The authors also comment at some length on various aspects of lichen 

 biology, on hal)itats, and plant-associations, as represented by some heath- 

 forms, tree-dwellers, etc. In reference to " aspect " they find that 

 yellow-coloured lichens appear to revel in full sunhght, while some green 

 Parmeliae prefer the north and west sides of tree-trunks. The fruiting 



* Journ. Bot., li. (1913) pp. 248-53. 



t Sci. Proc. Koy. Dublin Soc, xiv. (1913) pp. 79-143 (1 map and 7 pis.). 



X Essex Nat., xvii. (1913) pp. 90-105. 



