202 Transactions British Mycological Society. 
to have put the matter to the proof. He recognizes two types 
of such lichens: (1) ornithocoprophilous and (2) coniophilous. 
The first mentioned lichens occur on rocks by the sea frequented 
by birds. A sketch is given of the succession of vegetation. On 
the summit and on the more level parts of the rocks the alga, 
Prasiola, appears first, followed by lichens such as Rhizocarpon 
spp. To Rhizocarpon succeed Lecanora cinerea and Parmelia 
saxatilis, the cinerea-saxatilis formation largely usurping the 
place of previous growths. The steep rock-faces are occupied by 
Parmelia fuliginosa and the base by Bacidia inundata. 
If the rocks are frequented by birds the cinerea-saxatilis 
formation is accompanied or replaced by a Lecanora saxicola 
formation, feebly coprophilous, and by Physcia stellaris var. 
ascendens, strongly coprophilous, these two formations including 
also species of Caloplaca (Placodium) (vitellina, cerina, ferru- 
ginea),and byathird formation, Ramalina polymorpha-X anthoria 
lychnea also strongly coprophilous, on more strongly wind-swept 
areas than the others. To test these lichens Sernander watered 
them every evening for a month with a concentrated solution 
of crow excreta. At the end of the time most of the Parmeliae, 
Lecanorae etc. were unhealthy or dead, while Lecanora saxicola, 
Caloplaca spp. and Xanthoria spp. were in good condition. 
Comparing tree lichens with those, he found that on fre- 
quented roads, where dung laden dust was abundant, the lichens 
that flourished best were Physcia ascendens, Ph. ciliaris, Xan- 
thoria lychnea and X. panietina, which he classifies as “conio- 
philous” species. He gives a further list of those he considers 
as hemi-nitrophilous. 
Nienburg (1919) confirms Sernander’s results, he adds Ra- 
malina fraxinea as also coniophilous. He found nitrophilous 
lichens on trees that have wounds on the trunk in which 
ammoniacal substances are developed, and these when diluted by 
rain stream down the trunk killing all the lichens in their course 
except the nitrophilous species. Gallge (1920), in his account of 
Iceland lichens, rather objects to “nitrophilous,”’ “halophilous”’ 
etc. as names for associations owing to the difficulty of deter- 
mining the dividing line, all lichens being, he says, nitrophilous 
to some degree. Gallge prefers for associations the terms crus- 
taceous, foliose, and fruticose, with formations named after the 
dominant forms. Tree lichens were rare in Iceland, rock lichens 
abundant. 
Savicz (1913) in a paper on the lichens of Pskov gives a 
description of turf moors on which he recognizes three lichen 
formations: (1) a Sphagnum formation with Cladonia rangiferina, 
Cl. sylvatica and Cl. alpestris (these compete with the Sphagnum 
and grow to large dimensions); (2) a shrub formation with 
