CHAP. Lxxxviii MAT- VEGETATION 321 



Mat-vegetation of the Alps. 



The distinction between mat- vegetation and meadow is not great, 

 but mat-vegetation is shorter, so that it is essentially suited for grazing 

 purposes and not for mowing. Mat-vegetation passes over into certain 

 subglacial communities, as is natural, since it often occurs among these 

 and forms their continuation lower down mountains, where, in fact, the 

 conditions are more favourable to growth. As a typical example one may 

 mention Kerner's ^ Carex ferruginea-' formation ', which includes Solda- 

 nella alpina, Gentiana acaulis, alpine auriculas, alpine anemones, Nigri- 

 tella, Globularia nudicauhs, Phaca frigida, Lotus corniculatus, and other 

 herbs, with Sesleria coerulea, Festuca violacea, F. pulchella, and other 

 grasses ; in it one can also find stray dwarf-shrubs or prostrate under- 

 shrubs, such as Erica carnea, Sahx reticulata, S. retusa, Dryas, or others. 



In the same category may be reckoned Stebler and Schroter's ^ Leon- 

 todon mat-vegetation, which is composed of Leontodon hispidus, L. 

 autumnalis, L. pyrenaicus, Crepis aurea, Homogyne alpina, Ligusticum 

 Mutelhna, species of Potentilla, Geum, Sibbaldia, and Plantago, also 

 Soldanella alpina, Veronica alpina, and Polygonum viviparum, as well 

 as grasses. 



As mat-vegetation many botanists regard a number of communities 

 which are, to some extent, of a different oecological stamp, and probably 

 should be regarded as belonging to a different type of community. Stebler 

 and Schroter discuss, inter alia, the following communities : 



1. Nardus s/nd-association (nardetum), which grows on poor dry soil, 

 and often alternates with rhododendrons or with dwarf-shrub heath. 

 Scattered about this vegetation are Potentilla aurea, P. sylvestris, Calluna 

 vulgaris, Leontodon pyrenaicus, Trifolium alpinum, Geum montanum. 

 Arnica montana, Homogyne alpina, and Lycopodium alpinum ; such 

 grasses as Aira, Anthoxanthum odoratum, and Festuca rubra ; Luzula 



1 albida and L. spicata ; masses of lichens belonging to the genera Cladonia 

 i and Cetraria ; and species of Vaccinium. This association, in many 

 respects, is allied to heath or to a community of chersophytes. 



2. Carex /^rwa-association,^ in dry spots on hmestone mountains, at 

 altitudes of 2,000 to 2,900 metres, assumes the form of the topmost 

 continuous carpet of dense, low, caespitose plants with short, stiff leaves. 

 Accompanying Carex firma are Elyna spicata, Festuca pumila which 

 forms fine-leaved tufts Carex nigra, and other grass-hke plants ; also, 

 ' scattered like pearls in the emerald sward,' a number of species of 

 Saxifraga and Gentiana, Alsine verna. Campanula Scheuchzeri, Primula 

 integrifoha, and others. 



These two communities obviously betray some degree of xerophytism, 

 nd possibly it would be most correct to reckon the former as xerophytic 

 iid as constituting a special type of subglacial community. 



According toBrockmann-Jerosch,^ in Switzerland there are many types 

 if meadows which correspond to various combinations of factors. Ex- 

 )usure plays a great part, because of the strong insolation and because 



.11 



' Kerner, 1863. * Stebler unci Schroter, 189; 



' Brockmann-Jerosch, 1907.* 



WARMING Y 



