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 l Carex ferruginea-' formation ', which includes Solda- 

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

 tella, Globularia nudicaulis, 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, Salix reticulata, S. retusa, Dryas, or others. 



In the same category may be reckoned Stebler and Schroter's 2 Leon- 

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

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

 Mutellina, 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^ncta-association (nardetum), which grows on poor dry soil, 

 and often alternates with rhododendrons or with dwar^-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 

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

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

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



2. Carex /rm-association, in dry spots on limestone 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-like plants ; also, 

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

 Saxifraga and Gentiana, Alsine verna, Campanula Scheuchzeri, Primula 

 integrifolia, and others. 



These two communities obviously betray some degree of xerophytism, 

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

 and as constituting a special type of subglacial community. 



According toBrockmann-Jerosch, 3 in Switzerland there are many types 

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

 posure plays a great part, because of the strong insolation and because 



1 Kerner, 1863. 8 Stebler und Schroter, 1892. 



1 Brockmann-Jerosch, 1907. 



WARMING Y 



