8 THE LICHENS OF PERTHSHIRE 
into three climatic zones, which he designated as follow 
e zone of sbiesaagoeen and pasture. 2. ne of Neeet 
moorland associations. 3. The zone of Aretic- gna vegetation. 
These apparently Siiesapaad id to Schimper’s lowland, montane, 
and alpine belts te he climates, and H. C. Watson’s 
Agrarian and Are 
. Gone of Gulioaien and Pasture. —This zone embraces all 
the lowlands, and terminates in a very irregular line, usually 
between the 900 ft. and 1200 ft. contours. Tt follows roughly the 
limit of corn cultivation and of Pieris in exposed situations, 
S st 
ore, Tummel, and Tay, and borders the courses of the chief 
rivers, extending in places a considerable distance Bp: the glens. 
n this zone the influence of man reaches its maximum effect on 
i a and the natural peta as meee are sometimes diffi- 
up and drained. Such as remain yield the following pete 
characteristic of peat-bogs :—Baomyces ee Cladon 
pityrea, C. cornuta, C. cervicornis, C. trachyna, C. say hy 
C. fure C. racemosa, C. crispata, C. squ “i c. cifera, 
C. pleurota, C. bacil C. Floer ,C rangiferina, 
laris kea ladin ife 
. empexa, C. sylvatica, C. ‘alpestris, C. uncialis, he aculeata, 
Lecidea glaucolepidea, L. granulosa, and L. aon 
The nitrophilous lichens are more prevalent in this low 
zone than in the others. They probably oeitadls inhabited 
maritime rocks, where the spray was eat rged with the Rese. 
of the marine fauna and the dung of sea-fowl. They now fin da 
satisfactory food supply in the Repel of highly eulti- 
vate fields and by dung- strewn roads, where ha wn dust con- 
Xanthoria parietina, X. lychnea, Physcia tenella, P. puloerulenta, 
P. aipolia, Placodium murorum, P. tegulare, P. sym 
Callopdeintain citrinum, C. vitellinu wm, C. lacin ~— C. fer pdt: 
gineum, C. pyraceum, Lecanora circinata, L. galactina, L. 
Buellia canescens, er probably some other Aaah of fli. 
On roadside banks Cladonia pyxidata, C. fimbriata, and C. ces 
titia often grow very freely, ut they also may be so ne 
nitrophilous, and, as pointed out by W. West, some Parmelia 
are a ae abundant and iecelouk on roadside trees and walls than 
elsew 
The + woodlands form an important feature of this zon 
have not Sieur et to define the lichens of ~ different pens a 
woods. woods the lichens are most numerous in species 
and also in individuals (with the exception, geen tel of Usnea 
