314 



INDEX 



subgrcganous, 205 

 submerged plants, 168 

 succession, 273 



abnormal, 274 



by cultivation, 282 



due to man, 280 



in aeolian soils, 278 



in alluvial soils, 277 



in burned areas, 281 



in coUuvial soils, 276 



in eroded soils, 279 



in flooded soils, 280 



in lumbered areas, 282 



kinds of, 274 



laws of, 284 



method of alternating stages, 286 



normal, 274 



primary, 274, 275 



relict method, 287 



secondary, 275, 278 



study of, 286 

 succulent form, 159, 164 

 sugar, 103 

 sulphates, 19, 101 

 sulphur, 18, 101 

 sum of temperatures, 97 

 summer aspect, 224 

 sun leaves, 178 

 sun plants, 165, 183 

 support, 54 

 surface, 22 



influence of, 23 

 symbiosis, 104 

 symmetry in vegetation, 298 



physiographic, 298 



Tamarix, 162 

 Taraxacum., 121, 182, 242 



taraxacum, 182 

 Teleonyx jamesii, 88 

 temperature, 5, 25 



adjustment to, 90 



effect of low, 98 



favorable and unfavorable, 95 



influence of clouds, winds, etc., 95 



influence on vegetation, 98 



maximum and minimum, 95 



measurement of, 91 



of the air, 91 



of the plant, 92 



of soils, 92 



sum of, 97 



variations of, 94 

 tendrils, 141 



sensory area, 141 

 Tetraneuris, 159 

 Tetraspora, 237 

 Teucrium, 120 

 texture of soil, 15, 20 

 Thalictrum, 178 



Thalwtrum sparsiflorum, 179 



thermometer, 91 



thermotropic plants, 91 



thorn form, 164 



Thuja, 162 



Tilia, 120 



time of daily flowering, 130 



tonic action, 2 



tracheary vessels, 53 



Tradescantia, 122 



transect, 210 



belt, 211 



line, 210 

 translocation, 83 

 transpiration, 56 



adjustment to, 69 



amount of, 66 



compensation for increased, 68 



influence of physical factors, 63 



measurement of, 64; in field, 65 



relation between absorption and , 68 

 transpiring surface, 59 

 transport, 50, 54 

 Tribulus, 243 

 trypsin, 100 

 tuber, 115 



turgescent fruits, 247 

 turgidity, 48, 61, 68 

 types of formations, 232 



of leaf xerophytes, 156 



of leaves as determined by light, 

 182 



of plant body, 154 



of stem xerophytes, 162 



produced by adaptation to water, 

 155 

 Tijpha, 126, 242 



Ulothrix, 243 

 Umbclliferce, 242 

 Vmhilicaria, 215 

 unisexual crosses, 197 

 Urtica, 126 

 utricle, 132 



Vaucheria, 243 

 variability, fluctuating, 189 

 variants, 196 

 variation, definite, 189 



indefinite, 189 



origin by, 195 

 vegetation, development and struc- 

 ture, 219 



effect of temperature on, 98 



form, 155, 265 



historical factor in, 219 



influence of vegetation form on 

 competition, 256 



methods of studying, 202 



pressure, 257 



