Grazing [Contin.) 



continuous, 114 



effect on competition, 33, 46-47 



effect on growth-form, 96 



effects of, 44-49 

 Great Basin, United States, 12 

 Great Britain, 21, 37, 41, 44, 48, 57, 



93, 141 

 Great Plains, 24, 26, 29, 30, 44, 46, 

 48, 62, 68, 72, 92, 96, 98, 103, 

 130, 140, 181 

 Great Smoky Mountains, 142 

 Greenland, 36, 139, 159, 187 

 Gregariousness, 77, 96-98 

 Gnndelia squarrosa (Gum weed), 145 

 Ground-water level, 62 

 Grouping of species, 59-74 



definition, 59 



effects of parasites, 52 

 kinds of, 64-65 

 Growing season, 89 

 Growth curve, 105, 106 

 Growth-form, 42, 49, 77, 92, 96, 159 

 Gutierrezia sarothrae (Broom snake- 

 weed), 145 



Habitat, adaptation to, 56 



alteration of, 15, 48, 139, 141, 146- 



147, 153-155, 166 

 basis of classification, 181-182 

 changes in and succession, 150-151, 



177, 186 

 definition, 137 

 major, 137 

 micro-, 24, 96 

 minor, 137 

 similarity of, 66-67 

 steady-state, 141 

 Habitat-form, 77, 92, 95 

 Hamamelis virginiana (Common witch- 

 hazel), 83 

 Hauptassoziationen, 180-181 

 Hawaii, 53 

 Heath, 62, 72 

 Heather. See Calluna 

 Hedeoma hispida (Rough pennyroyal), 



84, 128 

 Height of plants, 49, 105-108, 118, 

 128, 130 

 and cover, 108-109 



Height-weight ratio of plants, 89, 90, 

 108-110 



Helianthns (Sunflowers), 37, 97 

 (common S.), 184 



Hemicryptophyte, 94 



Hemixerophyte, 95 



Hemlock. See Tsuga 



Heterogeneity of vegetation, 67, 70, 

 172 



Hibernal aspect, 87 



Hiemal aspect, 87 



H liana 

 jamesii (galleta grass), 85; mutica 

 (tobosa grass), 89 



Homoclime, 14, 58 



Homogeneity, floristic, 125, 127, 156, 

 163 

 and the normal frequency ratio, 1 14 



Hordeum brachyantherum (Annual mead- 

 ow barley), 39 



Horizon, A2, B2, 144 



Hybrids, 44 



Hybridization, 25 

 introgressive, 43 



Hydrangea arborescens (Smooth hydran- 

 gea), 83 



Hydrophyte, 11,93,95 



Hydrosere, 140, 151-152 



Hyperadaptation, 15 



Hypertrophy, 53 



laroshenko, P. D., 136 

 Iceland, 159 



Idaho, 19, 31,47, 73,88, 101, 104 

 Ilex (Hollies) 



opaca (American H.), 83; vomitoria 

 (yaupon), 20 

 Illinois, 155 

 Index, association, 99 



frequency, 112 



frequency-abundance, 115-116 



of similarity, 99 

 Indicator plants, 91, 99, 140-141 

 Integration, ecological, 2 



and ecological success of species, 

 54-55 

 Interaction, and groupings of species, 

 61-62 



kinds of, 7, 26 

 Interdigitation in vegetation, 1 1 2 



210 • Index 



