274 THE JOURNAL OF BOTANY 



latter was not in distinct patches as I have seen it on the Dovraf- 

 jeld, but was nestling in a very scattered manner among Bhacomi- 

 triun lanuginosum. 



On the slope immediately below the summit for some distance 

 towards Eonas Voe the ground was very bare, about six square 

 yards of bareness to every square yard of vegetation, the ground 

 being regularly terraced in some places. The plant covering the 

 granite dehris was chiefly Bhacomitrium lanuginosum, but scattered 

 about it was Festuca ovina (viviparous), very dwarfed Plantago 

 maritima, Thymus Serpyllum, tiny Calkma, and occasionally 

 Agrostis tenuis or Empetrum. 



On that side of the ascent from Colla Firth there was one 

 somewhat flattish place of some extent paved with rough granite 

 debris. On this Arctostapliylos Uva-ursi was quite as dominant 

 as Calluna, in some places more so. Here Bhacomitrium lanugi- 

 nositm was undoubtedly the dominant plant (40), Arctostaphylos 

 Uva-ursi (20 + ), Calluna (20 — ), Erica cinerea (10) ; the remaining 

 plants (10) were, along with a certain amount of bareness, Nardus, 

 Molinia (barren), Scirpus ccespitosus, Potentilla sylvestris, and 

 Festuca ovina (viviparous). Here and there among the Bhacomi- 

 trium were patches of Cladina sylvatica. 



Another part of the slope at some distance was examined on 

 the same kind of soil; the dominant plants were about equal 

 quantities of Calluna and Bhacomitrium lanuginosum ; the rest of 

 the plants were very scattered, though at times quite equal and 

 often exceeding — collectively — the two plants already mentioned ; 

 they consisted of a mixture of Nardus, Sieglingia, Scirpus ccespi- 

 tosits, Potentilla sylvestris, and Agrostis tenuis. Narthecium, 

 Molinia, and Erica cinerea only occurred here and there, with a 

 little E. Tetralix in the slight hollows. Festuca appeared to be 

 absent, Carex flacca, C. echinata (attacked by Ustilago Caricis), 

 and one or two other over-ripe species were scattered about. On 

 this part of the hill were some hard granite boulders, on which 

 were Andrecea rupestris, Hedioigia ciliata, Parmelia lanata, P. 

 triste, P. saxatilis, P. omphalodes, P. fuliginosa, Gyrophora torre- 

 facta in abundance, with much less G. flocculosa and G. cyUndrica. 

 Parmelia saxatilis and P. omphalodes were often creeping over 

 masses of old Bhacomitriicm lanuginosum, which covered small 

 rocks. Lecanora tartarea was rare on these granite rocks. Bhizo- 

 carpon poly car pum was more frequent, growing intermingled with 

 B. geographicum ; the latter was also often mixed with Lecidea 

 rivulosa. This latter sometimes was the only plant which covered 

 the rocks. One large boulder of granite was almost covered with an 

 association of Lecidea polycarpa, L. lactea, and Lecanora alhella. 



The rocks near the shore in both Unst and the Mainland 

 subject to the action of the tides and the spray of storms were 

 examined in several places. The lichens noted were those one 

 usually finds in such situations, with the exception of Lichnia 

 pygmcea, which was not seen ; it is usually at a lower zone than 

 L. confinis, which occurred but sparingly. Verrucaria maura was 

 everywhere, sometimes associated with Lecanora decipiens, some* 



