INDEX. 



703 



Punctum vegetationis, 338, 419 

 Pycnidia, 604 

 Pyrenomycetes, 623 

 Pyrocatechin, 228 



Pyronema (Peziza) confluent, reproduc- 

 tion of, 621 



Pythium, reproduction of (Fig. 72)5619 

 Pythium intermedium, 605 

 Pythium proliferiim, life-history of, 634 



Quassiin, 243 



Radial organs, 42 2 



Radides, irritability of, 492 



Radlkofer, on crystalloids in Lathrcea 

 squamarict) 171 



Rameaux, on loss of heat in transpira- 

 tion, 313 



Ranke, on electrical condition of plants, 

 320, 322, 325 



Raphe of Diatom-frustule, 520 



Raphides, 29 



Rautenberg, on chemical action of roots 

 on solutions, 56 



Rauwenhoff 



on absorption of carbon dioxide by 

 plants, 82 



on absorption of oxygen by seeds, 



76,77 



on direction of growth in darkness 

 and in light, 441 

 on etiolation, 268 

 on etiolated shoots, 387, 392 

 on evolution of ammonia by ger- 

 minating seeds, 210 



on growth of leaves in darkness, 

 381 



on influence of light on growth, 396 

 Receptive spot, 609 

 von Rechenberg 



on fatty acids in seeds, 190, 220 

 Rectipetality, 418 

 Rees, on tyloses, 350 (Fig. 40) 

 Reinke 



on glycogen in yEthalium, 1 7 1 

 on imbibition, 38 

 on lecithin, 131 

 on plastin, 25 

 on xanthin, 221 

 Relation of offspring to the two parents, 



650 

 Renard, on formation of sugar from tri- 



oxymethylene, 144 



Reproduction, 6, 597 ; sexual, 600 ; 

 spore-, 597; vegetative, 597; theo- 

 ries of, 653 



Reproduction in, Algae (Figs, 65, 66, 

 67, 69), 605, 612; in Angiosperms, 

 (Figs. 70, 75), 615, 643; in Fungi 



(Figs. 72, 73, 74), 617; in Gymno- 

 sperms (Figs. 71, 76), 615, 643; in 

 Phanerogams, 603, 615, 640, 643 



Reproductive cells, 597; organs, 60 1 ; 

 substance, 660 



Reserve materials, 140, 170 



Resin-duct, structure of (Fig. 31), 245 



Resin-grains, 232 



Resins, 236 



Respiration, 195; relation of, to growth, 

 2 95 369; to movement, 297 



influence on, of absorbed salts, 202; 

 of reserve-materials, 204 ; of tem- 

 perature, 198 



Reversal of direction of torsion, 516; 

 of twining, 517 



Reversion, 652 



Revolving nutation, 361 



Rheotropism, 473, 528 



Rhizomes, diageotropism of, 463 



Richter, on refraction of crystoliths, 22 



Ricinus, aleurone -grains of (Fig. 29), 

 184 



Ringing experiments, 97, 169 (Fig. 25) 



de la Rive, on conductivity of wood, 316 



Rischawi 



on evolution of carbon dioxide by 

 wheat-seedlings, 199, 201 



on optimum temperature of growth, 



295 



Robinia, paraheliotropism of, 552, 593 

 Rodewald, on xanthin, 221 

 Root, structure of (Fig. 20), 93 ; aerial 



(Fig. 12), 50; parasitic, 51 

 Root-hairs (Figs. 10, n), 46; acidity 



of, 55 

 Root-pressure, 90 ; daily periodicity of, 



95. 407 



Root-tip, localisation of irritability in, 

 468, 474, 479 



Roots, absorption by, 53 ; Darwinian 

 curvature of, 492; decapitated, cur- 

 vatures in, 468, 492 ; distribution of, 

 in soil, 51 ; external directive influ- 

 ences on growth of, 500 ; geotropism 

 of, 458; heliotropism of, 428; hydro- 

 tropism of, 477; proper angle of 

 lateral, 421 



Rosanoff, on direction of movements of 

 plasmodia, 527 



Roscoe, on photochemical induction, 

 263 



Rostafinski, on Botrydium, 607 



Rotation of protoplasm, 297, 521, 558 



Ruberythric acid, 238 



Rumpf, on phosphorescence, 317 



Russow, on continuity of protoplasm, 

 586 



Rzentkowsky, on growth of leaves in 

 darkness, 382 



