8a6 



INDEX. 



Pith, elongation of, 573, 573. 

 Pit-canals, 92. 

 Pitted-vessels, 136. 

 Pits, 92, 423. 



— bordered, 137, 160, 237, 

 424. 



Plagiotropic organs, 698, 



703-705.711- 



— organs, rolled up, 706, 

 707, 709. 



— and orthotropic organs 

 contrasted, 705. 



Plagiotropism, 489, 492, 494, 



709, 710, 712, 713, 714- 

 Planariae, 298. 

 Plantago lanceolata, 129. 



— major, 220. 



— media, 792. 



— psyllium, 90. 

 Plant-life, external condi- 

 tions of, 189. 



Plants in the tropics, 197. 

 Plasmodia, 82, 429, 604, 



615. 



— irritability to light, &c., 



615. 



— movements of, 614. 

 Plasmolysis, 213, 567, 568, 



617,653. 



Plastic substances, 326, 329, 

 413, 767. 



active and passive con- 

 ditions of, 341. 



translocation of, 329, 



353, 357, 361. 

 Platanus, 166,279. 

 Platycerium IVillingkii, 32. 

 Plectranthusfruticosus, 121. 

 Plerome, 143, 420, 

 Plum, 90, 147. 

 Plumule, 3,41,332, 344, 414, 



492, 50s, 680, 694, 702, 



712, 717, 753, 764- 

 Pogostemon patschouti, 185. 

 Polarity, 481, 484, 485. 

 Polemoniacese, 780. 

 Pollen, 761, 789. 



— nuclei of, 761, 771. 



— protection of, 797. 



— grain, 76, 92, 98, 99, 739, 



751, 754, 756, 757, 758, 

 760-762, 769, 778. 



702. 



• development of, loi. 



mother-cells of, 433. 



— — sterile cells of, 756. 

 sacs, 757, 760. 



— -tube, 751, 754, 755, 756, 

 758, 760, 762, 768, 771- 



773, 778- 

 PoUmation, 329, 535, 538, 

 754, 757, 760, 781, 790, 

 792. 



— of Aristolochia, 792-794. 



Pollination of Orchids, 796, 



797- 



— of Salvia, 794. 



— ot Viola tricolor, 794, 795. 

 PoUinia, 796. 

 PoUinodium, 726, 727. 

 Polygonaceae, 55, 186, 419, 



465, 470. 

 Polygonatum, 60. 



— multiflorum, 61. 

 Polygonum, 640. 



— dumetorum, 672. 

 — fctgopyrum, 283. 



— scandens, 668. 



— Sieboldi, 543, 685. 

 Polypodium "vulgare, 131. 

 Poljporus borealij, 388. 



— dryadeus, 388. 

 — ful'vus, 388. 



— ignarius, 388. 



— mollis, 3B9. 



— sulphureus, 388. 



— -vaporarius, 388. 

 Polysiphonia, 335. 



Poplar, 146, 186, 225, 229, 

 319, 578, 582, 584, 703. 



Populus, 177, 319. 



Porosity of wood, 238. 



Porous bodies, 243. 



Portulacca, 640. 



Position of reproductive 

 organs, 787. 



Positive geotropism, 679- 

 681, 689-691, 703. 



— heliotropism, 693-695, 

 697, 70J, 709, 71Z, 713, 

 714. 



— hydrotropism, 717. 

 Post-embryonic configura- 

 tion, 528. 



— growth, 503. 



influence of environ- 

 ment on, 516, 528, 536, 

 537. 



Potamogeton, 297, 701, 



— natans, 51. 

 Potassium myronate, 342. 



— salts, 202, 226, 252, 260, 



262, 284, 287, 289, 290, 

 291,320,383. 

 in sap, 274. 



— sulphate, 342. 

 Potato, 58, 330, 333, 337. 



— 59, 165, 169, 273, 274, 

 277, 278, 314, 316, 326, 



333, 337, 339, 35o, 363, 



369, 390, 504, 507, 535, 



722, 798, 799. 



disease, 369, 381. 



Potentilla, 780. 

 Precipitation membranes, 



214. 

 Pressures on sieve-tubes, &c., 



360. 



Pressures as a stimulus, 503 

 515, 617. 



— and strains in cortex and 

 wood, 574-579. 



— in tissues, 362, 437, 581, 

 582. 



Prickles, 57, 125, 289. 

 Primary embryonic tissue, 

 417. 



— leaf, 747, 764- 



— meristem, 419, 770. 



— root, 418, 689, 690, 703, 



747, 752, 753, 764- 



— shoot axis, 747, 753, 

 Primordial leaf, 506. 

 Primrose, 186. 

 Primula auricula, i86, 



— elatior, 781, 

 — farinosa, 186. 



— marginata, i86, 



— officinalis, 781. 



— sinensis, 129, 184, 279, 

 790. 



184. 



Primulaceae, 780, 790. 

 Products of assimilation, 156, 



299, 314, 317, 357, 403, 



533, 763- 

 first visible, 306, 309, 



318. 



metamorphoses of, 3 2 3, 



Products of degradation, 



328, 329. 



— of fermentation, 348. 



— of metabolism, 316, 323, 

 330, 357. 



Pro-embryo, 735, 764. 

 Progressive development, 



467, 468. 

 Propagation of stimuli, 596- 



598, 646, 649, 662, 



663. 



— vegetative, 477, 723, 798, 

 800. 



Properties of hybrids, 783- 

 784. 



— of parents transmitted to 

 offspring, 779. 



— of wood, 234, 243. 

 Proportions of ash-constitu- 

 ents, 290. 



— of salts absorbed, 287. 

 Prosenchyma, 146. 

 Protandrous flowers, 792. 

 Proteaceae, 146. 

 Protection of growing-point, 



462. 



— of pollen, 797. 

 Proteid reserve-materials, 



332,345. 

 substances in parasites, 



&c., 372. 

 absorption of by insec- 

 tivorous plants, 374. 



