2 88 



INDEX. 



222 ; on direction of movements, 

 221 ; as an element of climate, 

 220, 221 ; liberated in respiration, 

 fermentation, intramolecular res- 

 piration, see tliese topics 



Heights of trees, 119 



Heliotaxis, 216. See Light 



Heliotropism, 213-215. See Light; 

 comparison with geotropism, 

 215 



Heredity, 279-283; definition, 279; 

 means, 279, 280; environmental 

 factors, 280; prenatal influences, 

 281; subsequent influences, 281- 

 283 



Hot springs, plants of, 220 



Humus, 78; humus plants, 78; asso- 

 ciation with other plants, 78-80 



Hydathodes, 128 



HYDKODICTYON, reproduction, 266- 

 268 



Hydrotaxis, 226 



Hydrotropism, 224-226; balance be- 

 tween, and geotropism, 224. See 

 Water 



Hygroscopic movements, 226 



Insectivorous plants, see Carnivorous 

 Intercellular spaces, 142, 143 

 Intramolecular respiration, 16. See 



Respiration 



Intramolecular respiration, 16 ; defini- 

 tion, 25, 26 ; inherent in all organ- 

 isms, 25; duration limited in 

 higher plants, 25, 27; substances 

 concerned in, 28; products, 8. 

 See Fermentation and Respiration 

 Inuliu, 160, 161 

 Iodine, in marine plants, 113 

 Iron, 101 ; as stimulant, 101 ; relation 

 to chlorophyll formation, 101; in- 

 crustations, 126 



Irritability, Chapter VI., 183-253; 

 possible physical reasons for, 

 184-186; effect on growth, 186. 



See Geotropism, Heliotropism, 

 Water currents, etc. 



Jamin's chains, 120 



Latent period, 201, 243 



Laticiferous tubes, 159, 160 



Leguminous plants, growth in steril- 

 ized and unsterilized soil, 75; 

 seeds of, 261. See Root-tuber- 

 cles 



Lenticels, 144 



Leptom, 158, 159 



Leptomin, 159 



Leucoplastids, 160 



Lichens, 91, 92 



Life, definition, 256; essential condi- 

 tions, 6 ; how limited, 254-256 



Light, one factor essential to life, 6; 

 relation to food manufacture, 50, 

 58-63, 69, 70; relation to chloro- 

 phyll, 52-58; component rays, 56; 

 values of different rays, 57 ; rela- 

 tion to chlorophyll formation, 57 ; 

 effect on organic substances, 208- 

 210; effect on rate of growth, 

 210-213; on form, 211; on perio- 

 dicity of growth, 211 ; on sub- 

 mersed aquatics, 211-213; on 

 germination, 213; on direction of 

 growth, 213-215; relation to geo- 

 tropism, 214; comparison of he- 

 liotropism and geotropism, 215; 

 effect on locomotion, 216; effect 

 on position of cell organs, 217, 

 218; comparison of heliotropism 

 and heliotaxis, 218, 219; influence 

 on reproduction, 264-268, 271- 

 276; on brilliancy of flowers, 274, 

 275 



Lime incrustations, 126 



Living, definition, 4 



Locomotion, influences affecting, see 

 Chemotaxis, Phototaxis, etc. 



