275 



These ^ half -fluid masses glided down into the valleys, the fine 

 material was mostly washed out, but the larger blocks of resistant 

 quartzite still remain in heaps and in the well-known "stone- 



runs or "stone rivers." 



The climate is extraordinarily suitable for peat-formation, and 

 in the extensive swampy areas the peat layers grow slowly and 

 surely, furnishing the inhabitants with their chief fuel. The 

 absence of forests is partly due to the strong wind storms, but 

 since similar storms occur on the Fuegian coasts, which are clad 

 with luxuriant forests, other factors must combine with the winds. 

 The peculiarities of the terrain and soil may be unfavourable for 

 tree growth. The absence of a permanent protective covering 

 of snow during the winter would also be inimical to many plants. 



The vegetation may be described as a steppe. The grass- 

 steppe is especially developed, but the grasses are often replaced 

 By Empetrum rub rum, and sometimes by Bolax glebaria, thus 

 merging into heaths. The characteristic plants of the heath 

 formation are evergreen, and so periodicity is little evident to 

 the eye. In his latter paper Skottsberg subdivides the vegetation 

 into the following associations : 



Cortaderid-association is one of the most important types of 

 vegetation in the islands, being commonly developed on dried 

 ground, especially where the subsoil is composed of fine-grained 

 material. 



Empet rum-association is also found on comparatively dry 

 ground, being best developed on the mountain ridges and on stony 

 plateaux. It consists of dwarf shrubs, herbs and grasses. 



Chiliotrichum-association frequently forms a grey fringe along 

 fhe streams. 



Astelia-association is the Falkland representative of the peat- 

 mosses of high-moor type, but the Sphagnaceae are of little or no 

 importance. This association is partly responsible . for the 

 immense layers of peat which may reach several yards in 



thickness. 



Rostkovia-association is characteristic of the wettest ground, 

 being confined to the depressions, and corresponds to what is 



generally termed low-moor. 



Cortaderia-Astelia-RostJcovia-association is common on soil 

 intermediate in its moisture content and drainage between the 

 Cortaderia association and low-moor. 



Blechnum magellanicum-association inhabits ground round the 



quartzite ridges. 



The vegetation of the stone-runs is especially characterised by 



Nassauvia serpens. 



The alpine heath with Empetrum and Bolax covers the hill 

 tops, and most nearly resembles the tundra of South Georgia, 

 Kerguelen, etc. AzoreUa Selago and Valeriana sedifolia are 



confined to the highest summits. 



The fresh-water vegetation is not well developed. 



The vegetation of %he sea-coast has largely altered since the 

 advent of man and the introduction of domestic animals on the 

 islands. The tussock-grass, Poa fiabellata, once formed the most 

 important feature of coastal plant-life. At present it is only to 



c 



