TO Botanical Society of Edinburgh : — 



to a somewhat Alpine zone, which usually commences at a greatet 

 elevation than that of the highest ground on the islands. The 

 region in which the Cladonia ranyiferina^ Lecanora tartarea, Lecidea 

 geoyraphictty Sphcerophoron coralloides^ Parmelia omphalodes, &c., 

 prevail in the greatest quantity, and attain to their greatest luxuriance 

 and beauty, commences at about 500 feet, and terminates at a height 

 of 1000 feet or a little more. Of course, extensive patches of these 

 Lichens may sometimes be found at much lower elevations ; indeed, 

 I have repeatedly gathered considerable quantities of each of them, 

 but very diminutive and ill-developed, all along the west coast of 

 Scotland in immediate proximity to the sea ; but it is only within the 

 above limits that uniformly large and perfect specimens, furnished 

 with fructification, can be obtained. There are two Lichens occurring 

 on these islands which are found on almost all our sea-coasts, and are 

 never found far inland, the Parmelia aquila and Ramalina scopulorum. 

 The former has never been found, I believe, at a greater distance from 

 the sea than some twenty or thirty miles, and always grows on rocks 

 fully exposed to the sea-breeze ; it is found in considerable abundance 

 on rocks so situated on Arthur's Seat. The latter lichen is peculiarly 

 plentiful upon rocks along the west coast of Scotland, and attains a 

 greater length and thickness in proportion as we advance northward, 

 the Orcadian rocks being sometimes covered with individuals from 

 six to eight inches long, and nearly one broad. The specimens ob- 

 tained in the Cumbraes are among the longest and shrubbiest I have 

 ever seen, and present a remarkable contrast to those gathered on 

 the east coast, and especially along the Frith of Forth, where it is 

 rare to find an individual above an inch high, and with lateral 

 branches. The fructification is rather uncommon, and occurs, I 

 believe, more frequently on small and well-grown individuals, than 

 on those which attain the greatest length ; the thallus, in the case 

 of the latter, commonly developing new elongated branches at the 

 points of the margin where apothecia ought to have been produced. 

 The specimens found in the Western Islands differ considerably from 

 those collected on the Irish coasts, in being much narrower, of a 

 paler colour, and destitute of the oblong pale pitted buds, which 

 give a rough appearance to the aged Irish plant, and also in the disk 

 of the apothecia being of a much lighter colour, and nearly similar 

 to the thallus. It is a very variable species, however, if species it 

 can be truly called, presenting slight differences as regards size, colour, 

 shape, and mode of branching, on almost every coast. I have ob- 

 served in Menzies' Herbarium at the Botanic Garden, a specimen 

 marked ^R. scopulorumV collected on the coast of California, which 

 appears to me to differ very little from certain states of our native 

 plant, except perhaps in the thallus being a little thinner, softer, and 

 somewhat lacunose ; and I possess specimens collected in New Zealand 

 i^nd the Antarctic regions, which, making the usual allowances for the 

 widely different circumstances in which they were developed, may 

 safely be referred to one or other of the numerous states of our own 

 R, scopulorum. 



" By far the most interesting rarity found in these islands, how- 



