362 INDEX. 



tions of ft plant, 49 — ^limits of, endurable by plants, 80 — ^limit 

 of, below whicb plants will not grow, 81 — effects of one loc 

 high on plants, 81 — unnaturally low, its effects, 83 — relatively 

 Iiigh, conjoined with dryness, favours the formation of secre 

 tions, 83 — at which different fluids become frozen, 85 — its laws 

 with respect to its influence on vegetation, 87 — its alteriintiuiis 

 necessary to plants, 88 — of the earth at various places imnitui 

 ately below the surface, 91— effects of its diurnal nltei'iiations, 

 87 — ^effects of its annual alternations, 88 — of the earth, 90, iKi — 

 at various places, comparatively with that of the atmospheji-, 

 91 — at various depths, 92 — of tlie hottest and coldest montlis at 

 various places, 100 — ^importance of insuring a proper one lor 

 plants, 108 — of soils, its important influence on vegetiitiou, 108 

 — with regard to the direction of tlie wind, 130, 134— of hot- 

 houses, its regulation, 142 — effects of a high one at night in hot- 

 houses, 145 — effects on pollen of one too low, 171 — which grain 

 will bear, 181 — seasons of extreme, 320 — uniform, 320 — '.<jw. 

 with much light, its effects on the sap, 325 — of plant liouscs, ne- 

 cessity of lowering it during the night, 328 — diurnal extremes 

 of, 328. 



Tissue, general distension of, in the embryo stale of roots, 9 — general 

 distension of, in roots growing in air and water, 13 — ii.s hyero- 

 metrical force depends on the action of capillary tubes, 16. 



Tissue, its first foi'mation requires nitrogen, 18 — disorganisation of, 

 117 — impermeability of, induced by training, 2B5 — cellular, is 

 the comjjonent of the first rudiments of the stem, 21. 



Tonguing, 217. 



Training, 257 — on a horizontal plane, bad effects of, 257 — its effects 

 on the circulation of the juices, 259 — pendulous, 260 — its disau- 

 vantages, 266. 



Ti-ausplanted trees, then- pruning, 248— languid from previous dry 

 ness, effects on, by the too rapid absorption of water, 294. 



Transplanting, 279--its rationale, 281 — season foi-, 283 — of deciduous 

 trees, 280 — manner of performing the operation, 290 — prepara- 

 tion of old trees for, 291. 



Trees and shrubs, distinct parts of their bark, 26. 



True sap, wholly generated in the leaves, 252. 



Tubers, 29. 



