112 CARL SKOTTSBERG, A BOTANICAL SURVEY OF THE FALKLAND ISLANDS. 



Stratigraphy : 



A; c. 10 cm. humus with rhizomes, roots etc. 



B: c. 50 cm. dense, firm peat, interwoven with roots of Rosfkovia and Juncus. 



C: c. 25 cm. loose peat, containing some anorganic matter but still used for burn- 



ing purposes. 

 D: Bottom layer, lacustrine clay with sparse plant-remnants. 



No microscopical study was made as the samples got löst with the »Antarctio. 

 Thus I do not know if the peat is formed by same kind of vegetation that 

 now inhabits the surface, or if climatic conditions and composition of vegetation 

 were different when the main supply of peat arose. In other places peat-layers are 

 much thicker, up to several metres. 



The Blecliimiii uiagellaiiicnin-cassociation (Pl. VIII) and the associations 

 on rock surface and in crevices. 



D'Urville noted and described the peculiar vegetation round the quartzite- 

 ridges (1. c. p. 583). And after him, both Birger and I have given attention to it. 

 The plant after which it has got its name is a beautiful fern with up to Va ra. long, 

 coriaceous, shining, dark green fronds; the variety found in the Falklands is called 

 setigerum on account of the dense cover of palese, likely to retain moisture. In 

 Western Patagonia this plant is common in rain-forest, where it assumes the shape 

 of a tree and attains the height of a man; Fuegian specimens have a short, stout stem, 

 while Falkland specimens hardly rise their fronds above the surrounding dwarf-shrubs. 

 It is remarkable that we do not find it at all in the deciduous-leaved forests of 

 Patagonia or Fuegia. The frequent occurrence of this marked rain-forest species is 

 thus somewhat astonishing; the reason for its absence from the central parts of the 

 Magellan lands is their cold winter; in the Falklands the winter is milder, but it is 

 easy to see that even here Bledmuin magellanicum, suffers much from the climate, 

 in the spring most of the leaves, which remain so fresli and green throughout the 

 year in the rainy Fuegian zone, appear to be killed by drought. 



The Blechnum magellanicum-aissocisitxon inhabits the ground round the quartzite- 

 ridges. Such places would easily be set down as very dry, and this is true of the 

 cracks and crevices in the rocks and of the patches of heath clothing the solid rock. 

 But Blecli7ium keeps to the foot of the rocks, and especially where there is shelter, 

 between the upraised quartzite-beds etc, and such localities are certainly not very 

 dry, but present a uniform degree of humidity without getting swampy. 



E very where, Blechnum magellanicum seems to be accompanied by the same spe- 

 cies; they can be divided into two groups, viz. such as grow in the fern-bed or 

 cover the soil, which consist of the same kind of peat as in the Emfetrum-h-Qd^th, 

 and the true petrophilous species, of which some are also found with Blechnum. 



11. Rocky ridges round Stanley Harbour and Port William. 



Greg.-soc. Blechnum magellanicum Si)ars. Bolax gummifera Empetrum ruhruni 



Cop. lestuca crccta Deschampsia flexuosa Luzulu alopecurus 



