998 



fullest development on the northern ones. It is a formation which 

 seems to be correlated with an insular and cool climate. Thiis in 

 Iceland it holds a more important place, and large areas are covcrcd 

 by it, especially the lava-fields, such as those described by Gron- 

 lund (1884, p. 136), Jonsson (1895, p. 70; 1900 p. 68 and p. 85; 

 1905 p. 40 and p. 53) and myself (Ostenfeld 1899, p. 245). 



The typical Grinimia-heath of the Færoes is easily recognised 

 and needs no long description. It passes over gradually into other 

 formations, and presents several more or less distinct transitions, 

 one of which is described below ; when this occurs its characteristic 

 features become effaced. 



Ex am pi es of Grimmia-heath: 



1. Klakken on Bordo, 400 m. above the se a. An elongated, 

 flat, genlle slope. Gr/'mmza-carpet of G. hypnoides, fissured by the wind 

 in many piaces so that the bare niountain-gravel is exposed. The most 

 common flowering piants in the moss-carpet are Empetnim and Salix 

 herbacea., rather frequent are: Polygonum viviparum, Thymus, Aira 

 flexuosa montana, Festuca ovina vivipara, Silene acaulis, Luzula spicata 

 and Vaccinium myrtillus pygmaeum; Isolated specimens were observcd of 

 Potentilla erecta, Viola silvestris, Galium saxatile, Loiseleuria procumbens, 

 Festuca rubra, Lycopodium selago, Ranunculus acer pumila, Nardus, 

 Agrostis canina, Alchimilla alpina, Luzula multiflora, Carex rigida, Py- 

 rola minor (sterile), Thalictrum alpinum, Saxifraga oppositifolia, S. hyp- 

 noides, Taraxacum sp., Euphrasia minima. Arabis petraea. 



2. Fuglo, the summit-plateau (620 m.). A large and nearly 

 flat expanse with numerous rocks projecting from the G ri m m ia-cav pei ^ ; 

 phanerogams represented by a few single piants, Empetnim being the 

 most frequent; other species noted: Carex rigida, Festuca ovina vivi- 

 para, Aira flexuosa montana, Salix herbacea. Thymus, Polygonum vivi- 

 parum, Armeria, Juncus triglumis (in rather moist piaces); also the 

 lichens: Thamnolia vermicularis, Cornicularia aculeata, Sphaerophoron 

 fragile, Cladonia sp. and Cetraria islandica. 



3. The summit of Mornefjæld, Vi der 6, about 700 m. An 

 elongated plateau with a thick moss-carpet of Grimmia hypnoides, flow- 

 ering piants few and scattered: Empetrum, Salix herbacea, Polygonum 

 viviparum, Nardus, Alchimilla alpina, Aira flexuosa montana, Agrostis 

 canina, Carex rigida, Taraxacum sp., Vaccinium myrtillus pygmaeum, 

 Loiseleuria, Thymus, Sibbaldia procumbens, Gnaphalium supinum, Fes- 

 tuca ovina vivipara, Vaccinium uliginosum microphyllum, Aira alpina, 

 Alchimilla færoensis, Poa alpina vivipara, Lycopodium selago and Poten- 

 tilla erecta; also lichens, including Thamnolia vermicularis, Cetraria is- 

 landica and Cladonia rangiferina. 



4. Holgafjæld on Bordo, slope about 380 m. attitude. Grimmia 

 ericoides the dominant species; also present Hylocomia and Grimmia 

 hypnoides (the latter quite a subordinate element in this case). The 

 following are the phanerogams, some of which are rather numerous: 



^ When the term »Grimmia-carpet« is used, it always indicates G. liypnoides. 



