420 



PLAN2' SOCIOLOGY 



Gymnomitrium varians, 122 

 Gymnostomum calcareum, 184 

 Gypsophila fastigiata, 186 



muralis, 364 



repens, 320 



siruthium, 186 



-Lepidium subulatum assn., 186 

 Gypsophilous plants, 186 

 Gypsum soils, 185 



swamps, 205 



vegetation, 185 

 Gyrophora arctica, 38, 241 



cirrhosa, 241 



cylindrica, 38, 241, 320 



-Cetraria noermoerica assn., 241 



erosa, 38 



hyperborea, 38 



proboscidea assn., 155 

 Gyrophoretum, 324 



H 



Habitat, concept of, 21 



measurable factors of, 82 

 Halacsya sendtneri, 189 

 Halicole species, 165 

 Halimocnemis, 201 

 Halocnemum strobilaceum, 197, 202 

 Haloid soil plants, 165 

 Halophyte problem, 192, 194 



vegetation of soda soils, 205 

 Halophytes, facultative, 193 



obligate, 194 



transpiration rate of, 192 



osmotic concentration of, 130 



salt optimum of, 194 



xeromorphic adaptations of, 192 

 Halophytic genera, 205 



shrub steppe, 311 



vegetation, 192 

 of deserts, 202 

 of Great Salt Lake, 199 

 of steppes, 202 

 Halostachys caspica assn., 202 

 Hamamelis virginiana, 333 

 Heat, absorption and radiation, 83 



coagulation, of protoplasm, 86 



injury, to plants, 85 



requirement, 93 



Heath burned, 281 



burning, effect of, 280 



Calluna, 38, 281 

 Hedera, 50, 296 



helix, 12, 49, 69, 131 

 Hedwigia albicans, 149 

 Hedysarum, 242 



obscurum, 71 

 Hekistothermic climate, 94 

 Heleocharis acicularis assn., 349 

 Helianthemion guttati, 376 

 Helianthemum alpestre, 71 



grandiflorum, 14 



hirtum, 68 

 Helianthus, 89 



subrhomboideus, 328 

 Helichrysum stoechas, 190 

 Heliophytes, 107, 236 

 Heliosciadietum, 375 

 Helloborus, 128 

 Helodrilus foetidus, 131 



lonnbergi, 233 

 Helotism, 6 



Hemicryptophyta, 191, 192 

 Hemicryptophyte, climate, 298 



region, 298 

 Hemicryptophytes, 289, 291 



as pioneers, 309 

 Hemiparasites, 296 

 Hemisaprophytes, 7 

 Hepatica, 102 

 Herniaria fruticosa, 186 

 Herpotrichia nigra, 119 

 Hibernal aspect, 49, 198 

 Hieracium, 63 



alpinum, 120 



glanduliferum, 72 

 Hierochloe alpina assn., 155 

 Higher units of vegetation, 370 

 Hildenbrandtia rivularis-Bodanella lau- 



terborni assn., 109 

 Hiller peat auger, 338 

 Hippocrepis comosa, 183 

 Hippophae, 211, 236, 330 



-Salix incana assn., 330 

 Hippuris, 290 

 Holcus mollis, 214 

 Holoschoenion, 375 

 Holoschoenus roinanus assn., 375 

 Homalia trichomanoides, 16 



