INDEX. 355 



Paving the soil, 120. 



Peas, securing a late crcp of, 124. 



Pendulous training, 260. 



Perspiration of plants supplied chiefly by the action of the spon- 

 gioles, 13 — a function performed by the leaves of plants, 40 — is 

 promoted by solar light, 41 — its amount in various species, 47- 

 49 — experiments on, 47-49^ — entirely obstructed when the air 

 is saturated with moisture, 49 — its amount is in proportion to 

 the intensity of the solar rays, 49 — commencement of its action, 

 114 — an important vital function of plants, 126 — affected by 

 wind, 129 — ^prevented by damp, 148 — excessive precautions 

 against, 204 — cold produced by, 257 — through young bark, 283 



Fine-apple, its habitat in a wild state, 232. 



Pine-apple stools, 210. 



Pines, grafting of, 237. 



Pistil, its parts and situation, 66. 



Pith, 28 — its production, 24 — in endogens is intermingled with tlia 

 woody fibre, 24 — distinct and central in exogens, 24^ 



Placenta, 76. 



Plant, its nature, S — mode of its birth detailed, 10. 



Plants, their power of producing roots from various parts, 14 — liable 

 to injury from contact with deleterious matters in the soil, 17 — 

 cannot exist long on pure water, 19 — the channel through which 

 all their ascending fluids are conducted, 27 — their healthiness 

 depends on the free action of the leaves, 40— decompose car- 

 bonic acid during the day, 42 — form carbonic acid during the 

 night, 42 — ^inhabiting shady situations, reason of their not en- 

 during full exposure to the sun, 44 — imbibe an excess of fluid 

 during the night, 49 — their capacity of bearing direct light is 

 variable in different species, 53— deciduous, 54 — commencement 

 of the period of their fructification, 63 — their limits of endurable 

 temperature, 80 — are penetrated in all directions by air passages, 

 102 — ^require a correspondence of temperature with that of the 

 countries of which they are natives, 105— of extreme chmates, 

 112 — growing on grass, 138 — growing below projecting shelter, 

 138 — in sitting-rooms, 148 — their cultivation in confined air, 

 151 — ^have universally a season of rest, 319 — their resting, 319 



their annual rest, 319 — diurnal rest, 327 — their r(«t neces> 



sary to flowering, 327 — some grow eijually well in different 



