S9i 



INDEX. 



Nitrogen, in excess the probable cause of 

 mildew, 550 



indispensable for the first for- 

 mation of tissue, 28 



its abimdanoe in young tissue, 



547 



proportion of, in rain-water, 28 



Niven, Mr., experiments by, in regard to 



the circulation of the sap, 48 

 Nodules in the bark of trees, 44 

 Nutmeg-tree, mode of packing the seeds 



of, 252 

 Nutritious matter in plants influences the 



production of flower-buds, 95 



Oak, instance of the power which the 

 bark possesses of repairing on 

 injury, 37 



timber, annual rate of growth of, 



416 



experiments on the relative 



strength of fast and slow 

 grown, 419 



fast grown, superior to slow 



grown, 416, 418 

 Odour of plants occasionally produces 

 unpleasant effects on peculiar consti- 

 tutions, 62 

 Oil-cake, as manure, 565 

 Oleraceous annuals, 166 

 Olive, auoient practice of grafting, 358 



grafted on the fig, explanation of 



this assertion, 347 



mode of propagating in Italy, 267 



One-shift system, 442 



principal points to be 



attended to, 443 

 Orangery, Count de Charolais's, 259 



instance of trees in, remaining 



for six years without air and 

 water, 259 

 Orange-tree, best stock for, 355 



'- hardiness of, 192 



injudicious treatment of, 136 



long vitality of, 259 



manure for, 566 



mode of increasing by bud- 



ding, 307 



natural temperature of the 



soil for, 136 



^— thrive amazingly in soil 



mixed with charcoal, 646 



—. „ trifacial, 359 



Origin of various kinds of vegetables, 466 



Ovary, 81 



.Ovules, 81 



Oxalic acid employed to promote the 



germination of seeds, 237 

 Oxide of iron, large proportion of, in a 

 soil in vhich the pine^apple thrives, 538 



Oxygen, derivation of its supply, 28 



employed to promote germina- 

 tion, 236 



extrication of, in leaves by solar 



light, 60 



inhaled by leaves in the absence 



of solar light, 60 

 is absorbed by leaves when their 



functions become languid 



through age, 79 

 is absorbed from water during 



the process of germination, 14 

 Oyster-shells, their use when pounded,637 



Paokino grafts, D'Albret's mode, 342 



growing plants for long voyages, 



257 



seeds, 245 



Poeonies, root-grafting of, 361 

 Pan-feeders, 433 



Parallel development of leaves, 66 

 Paulownia imperialis, mode of increasing 



from portions of its root, 282 

 Paving the soil, 171 



Peach-tree, cause of the enlargement of 

 the stem wherebudded, 361 



. mode of budding, 306 



mode of pruning, 384 



rules and directions for prun- 

 ing, 386 

 Pear-tree, efi^ects of puiching the laterals, 



378 

 • inarching the branches of, with 



young wood, 324 

 pruning of, 376 

 pyramid, French method of 



managing, 378 

 training of, 377 

 I, securing a late crop of, 176 

 Peat, from bogs not suited for gardening 

 purposes unless prepared, 533 



instances of rendering it productive, 



538 



■ in what its value consists, 535 



its composition and properties, 628 



not essential for American plants, 



531 

 Peat-charcoal as a deodoriser, 563 

 Pendulous training, 424 

 Pepin, M., his statement relative to the 



long vitality of certain plants, 259 

 Perspiration, a function performed by 

 the leaves of plants, 59 



an important vital function, 



177 

 arrested when the air is satu- 

 rated with moisture, 68, 

 211 



commencement of its action, 



164 



