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PLANT SOCIOLOGY 



Fig. 16. — Former CaUuna heath with Jiim'pprns commtinis in hypodispersion (fire scar 

 to right) in the Totengrund near W'ilscde. {Photo by M'cigold.) 



Fig. 17. — Homogeneous moss and lichen tundra at Svalbard, Spitzbergen; a, 7 m. 

 belt of bright yellow Lecanora polytropa; b, a 14 m. belt, dark crustoee lichen with 

 Rhizocarpon badioatrum, R. polycarpum, L. gibbosa, L. polytropa; c, a dark brown moss 

 and lichen belt, with wich-ly .si)rcadiiis: Oyrophora cylindrica, G. vro^a, G. arcfica, G. 

 hyptirborca, Uphai^roiwrua (jlubuxus. Rhacuntilriiim hujtnoidcs, etc. (.Photo by Lid,) 



