408 DR. LA^ITDEIl LTXBSAT OX THE 



As markedly deficient are the — ■ 



No. of 



Tribes. Genera. species. 



I. Gra;plidei 1, GrapJiis 1 



2. ArtJionia 2 



II. Collemacei 3. Collema 1 



III. Pi/renocarpei 4. Endocarjion 1 



5. Verruca ria 4 



IV. Parmelei 6. Stictinct 1 



7. Sticta 1 



There are also certain peculiarities of geographical or topogra- 

 phieal distribution which are worthy of note. 



In Iceland I found Platysma nivale overspreading in large 

 masses the deserts to the south-east of the Cemetery at Eeykjavik, 

 growing frequently where no phfenogams and no other cryptogams 

 could vegetate, usually associated with tufts or masses of Getraria 

 aculeata. Both lichens were sterile and dwarfish, however. Ce- 

 traria Islandica and Cladonia rangiferina, which one would ajpriori 

 have expected to luxuriate in such a locality, occurred sparingly, 

 the former especially usually intermixed with Bliacomitriwn lami- 

 ginosum, Bridel— a moss so abundant in Iceland that it occupies 

 very much the place of Cladonia rangiferina in other countries*. 

 The UmUlicarics are rare about Eeylijavik (Eeykjavik Observatory 

 5G feet Danish above sea-level) f. I found the apothecia of almost 

 all the crustaceous lichens collected more or less deformed; and 

 this peculiarity may be common in Iceland, as it is generally in 

 alpine countries. 



At Christiansand, in the extreme south of :N'orway, about parallel 

 of latitude 5S° (which passes through the south of Sutherland- 

 shire), and on granite, at the sea-level, the UmUlicanco (XJ.pus- 

 . tulata and spodoclroa) grow in profusion and to a great size. On 

 the other hand, on the DovreQeld and Haalangenfjeld, where 

 rather they would have been expected to luxuriate, I found them 

 very small in size, and very few both as regards species and iQ<li- 

 viduals +. In other words, they appeared to reach their maximum 

 development in the extreme south and at the sea-level, decreasing 



* The same moss, with its ally M. canescens, Hcdw., often attaining a length 

 of 1 foot, coTcrs the Fiiroese hills, according to Sir Walter Trevelyan. 



t A Danish foot is equal to 12f English inches ; so that it is a fraction larger; 

 but the difference is so shght that it may for such purposes as the present l)« 

 practically disregarded. 



X About Jerkin they are not common j and on tho Haalangenijeld I ionn^ 

 them small and disappearing. 







