INDEX. 



695 



Perspiration, Dr. Hales's experiments on, 



64-68 



is affected by winds, 186 



is promoted by solar light, 



60, 455 

 its amount is in proportion 



to the intensity of the 



solar raySj 67, 455 

 its amount regulated by the 



epidermis, 79 

 not performed at night, 69, 



514 



rate of, in a healthy plant, 73 



supplied chiefly by the action 



of the spongioles, 19 



through young bark, 448 



Petals, 81 



Phosphates, their effect on vegetation, 



559 

 Phosphoric acid abounds in all clay or 

 sand, 529 



its value as manure, 557 



Physiological principles upon which the 

 operations of horticulture essentially 

 depend, 133 

 Pigeon's dung as manure, 564 

 Pileorhize, 18 

 Pine-apple, application of waste steam to 



the forcing of, 151 

 -^— importance of the old stump 



for producing suckers, 302 



its habit in a wild state, 537 



ripening out of doors, at 



Bioton, 101 

 succeeds better unpotted, if 



supplied with a proper 



amount of bottom-heat, 



433 

 Pine, grafting of, 321 



instances of a root forming new 



layers of wood without the ex- 

 istence of a stem, 261 



method of striking, by cuttings, 297 



Pistil, its parts and situation, 81 

 Pith, 42 



distinct, and central in its formation, 



35 



in endogens is intermingled with 



woody fibre, 35 

 Placenta, 103 

 Plant, its nature, 5 



mode of its birth, 16 



Plantations, danger in thinning such as 

 have been crowded, 411 



directions for managing, 407 



Planting, ill effects of close, 409 

 Plants, all cultivated, require manure, 

 540 



alpine, difficulty in cultivating, 



218 



Plants, aphyllous, offices of leaves per- 



formed in, by the riud and 



epidermis, 34, 59 



artificial food for, 561 



are penetrated in all directions 



by air passages, 134 



at rest, require but little water, 169 



-^ cannot long exist on pure water, 



28 



capacity of bearing light, variable 



in different species, 79 



circumstances which advance or 



retard the flowering of, 93 • 



commencement of the period of 



their fructification, 92 



conditions required to preserve 



them in a torpid state, 257 



constitution of certain, undergoes 



considerable changes with age, 

 479 



cryptogamio, their mode of re- 



production, 11 



deciduous, 79 



decompose carbonic acid during 



the day, 59 

 deteriorate the air at night, 514 



do not grow naturally in the 



soil best suited for them, 534 



donotvitiate theair of rooms, 61 



do not wear out when artificially 



multiplied by division, 477 



effects of arsenic upon, 8 



effects of chloroform on, 8 



effects of cold, 113 



effects of coloured light on, 238, 



300 



effects of moonlight on, 63 



poisons on, 8 



- facts relating to the long vitality 



of, 259 



- fallacy of growing, in a confined 



atmosphere, 214 



- flowering season of, may be 



changed, 513 



- form carbonic acid during the 



night, 60 



■ grafted, should be similar in 



structure and constitution, 345 

 • greater portion of, not suscep- 

 tible of hybridisation, 500 



■ growing in water are protected 



from the usual cooling in- 

 fluences, 163 



scorched by 



sun's rays, 

 164 

 growing on grass, 199 

 growing under shelter, 199 

 have a tendency to variation, 

 486 



Q Q 2 



