Clare Island Survey — Lichenes. 14 5 



and Lecanorae. Pyrenu/a nitida was very common and very noticeable ; and 

 minute forms of other Pyrenocarpei covered the trunks and branches. In a 

 wood at Louisburgh a fallen tree-trunk was almost wholly occupied by 

 Collema nigrescens, and some fine gatherings of Coccocarpia plumbea, with its 

 thick leathery thallus, were secured at the same place. 



Not a few rare species were discovered in the mass of material examined. 

 Among these may be noted Arthonia subvarians, a parasitic species from 

 Castlebar, recorded previously in England ; Arthopyrenia leptotera, found on 

 rocks by the sea at Achill, previously recorded from Jersey ; A. microspila, also 

 new to Ireland, generally associated with Graphis (sp.), as is the specimen 

 collected at Castlebar. A well-marked species, Bacidia arceutina, was found 

 at Achill on the branch of a tree, and a variety on peaty ground also at Achill 

 has been determined as var. liypnea, though that plant has hitherto been 

 recorded as growing over mosses and hepatics on boulders. B. ntrogrisea was 

 collected at Castlebar and at Achill, the latter specimen sent by Mr. Wattam. 

 Two collections of B. umbrina were also made on rocks at Achill ; it is 

 distinguished by the long, narrow, coiled or vermiform spores. 



Bilimbia albidocariiea, with the subspecies chlorotwpoides, was discovered 

 by Charles Larbalestier in Galway. The subspecies was now again found at 

 Castlebar. Typical specimens of B. lignaria were growing on the ground at 

 Achill, and again at Clare Island ; a saxicolous form of the species was gathered 

 at Achill and Belclare, and should probably have varietal rank. A similar 

 specimen was named Lecidca saxigena by Uloth ; in both forms the blue-green 

 tips of the paraphyses are a marked and characteristic feature. Collemopsis 

 Schaereri was found on the limestone at Castlebar, a thin black crust 

 crowded with apothecia, and on the same habitat Gyalecta cicpidaris and 

 G. exanthematica, the latter well-marked by its fissured apothecia. Zccanora 

 gelida occurred in abundance on a stone wall at Belclare, easily known, even 

 when sterile, by the brown spreading cephalodia on the thallus. 



Microtlielia dissepta, a very rare lichen, dotted with its black fruits the 

 thallus of Bhizocarpon confervoides ; it is another of the lichens discovered by 

 Larbalestier in Galway. A soil lichen, first sent by W. West from Clare 

 Island, Pannularia microphylla, grew in fine abundance, and was subsequently 

 found also at Achill ; it forms a brown, compact crust of minute, closely packed 

 brown lobes, among which are seated the dark apothecia. 



A form of Pertusaria Wulfenii was collected on a wall at Belclare ; the 

 spores were so much larger (95-lOOju x 30-45/u.) than the size given by Crombie 

 that it seemed at first to be a new variety ; but Continental authors give a 

 much larger measurement for the spores of the species, and ours came well 

 within the limits. 



