INDEX 



44i 



Pollen tube of, Angiospcrms, 3(33, 

 364 (lig.). 365, 3C7 (fig.) ; 

 Conifers, 349 dig.), 350, 351 

 (fij?.), 353 ; Cycads, 325 (fig,), 

 326, 3^7 ffig-). 332. 



Pollination, by insects, 46, 361, 

 373 ; by water, 361 ; by wind, 

 3t>i, 373 ; of Angiosperms, 

 355,356,363,37^; of Conifers, 

 345, 348, 349, 350 ; of Cycads, 

 326; oi Lyginopteris, 330. 331. 



Pollination-drop, 332 ; of Conifers, 

 348 ; of Cycads, 326. 



PoUinia (of Orchids). 361, 362 (tig). 



Polyarch roots, 69, 70 (fig). 



Polyembryony, 371 (fig.), 372, 390. 



PolygonaceEE, 35O. 



Polygoimm, ovule of, 358 (fig.). 



Polvgoninn convolvulus, extrafloral 

 nectaries of, 148 ; petiole of, 



113 (fig-)- 

 Polypetalous Dicotyledons, 337. 

 Polypody {Polvpodium), 309 ; sori 



of, 291 (fig.), 293. 

 Polvporus, 2j^ ; P. sqiunuosus, 250 



' (fig-)- 

 Polysaccharides, 31, 43, 44, 48, 



231 ; hydrolysis of, 46, 48. 

 Polystictis versicolor. Plate fl. 

 Poiytrichum, 274 (fig.), 276, 2S6 ; 



P. juniperhimn, 269. 

 Pond-scums (Algs), 195 et scq. 

 Pond v;eed{Potaniogetoii) , stamen of, 



359 (fig-) i stem-structure of, 



17^, 174 (fig-)- 

 Pondweed - family (Potamogeton- 



aceae), 178. 

 Poplar (Popnlus). 130, 141. 142 ; 



vessels of, 28, 35 (fig.). 

 Poppy (Papaver), 61, 155, 359. 

 Poppy-family (Papaveracefe), 153, 



i'54- 

 Populations, inheritance among, 



378. 

 Populus, 130, 141, 142 ; vessels of, 



^8, 35 (fig-)- 

 Pores of. Liverworts, 273 (fig.) ; 



pollen-grains of Angiosperms, 



362 (fig.) ; sieve-plates, 28 ; 



stomata, 96, 98, 99 (fig.), 100. 

 Porogamy, 364 (Ag-)- 365- 

 Porometer, 99, 100. 

 Potamogeton, 359 (fig.) ; P. lucens, 



172 ; P. nataiis, 172, 174 (fig.) ; 



P. pectinalus, 172. 

 Potamogetonacea?, 178. 

 Potash, and callose, 82 ; and cork, 



136 ; and fats, 49. 



Potato {Solituiiiji titbcrnsitni), food- 

 content of, 41, 42 (fig.), 43, 50, 

 52, 53 ; starch of, 41, 42 (fig.). 



Potato-blight (Phyiophlhora iii- 

 festans). 230. 231, 253. 254; 

 structure and reproduction of, 

 234. 235 (fig.), 236. 



Potato-family (Solanacea:'), 58, 60, 

 61, 81. 



Preservation of fossil-plants, 312, 

 328 ; of plant-material, 404. 



Prickles, 104. 



Pricklv Pear, 392. 



Prickly Saltwort {Salsola kali), leaf 

 of, 94, 166. 



Primary endosperm nucleus (of 

 Angiosperms), 366 (fig.). 



Primary medullary rays, 76. 78 

 (fig.), 118; of Conifers, 340; 

 of secondarily thickened stems, 

 119 (fig.), 120, 122, 124; of 

 .secondarily thickened roots, 



132- 

 Primrose (Primula), hairs of, 105 

 (fig.) ; hybrids of, 387, 388 



(fig-)- 

 Primulacea?, 356. 

 Procambial strands, 89, 90, 117, 



171. 

 Proembryo of, Angiosperms, 368, 



369 (fig.), 371 (fig-). 372 ; 



Conifers, 350, 351 (fig.) ; 

 Cycads, 327 (fig.). 



Prop-roots, structure of , 73, 74 (lig.). 



Prosenchymatous cells, 27, 32, 37. 



Proteaces, distribution of, 394 (fig.)- 



Proteases, 53. 



Protection against, animals, 39, 48, 

 58, 64, :o4, 106, 126, 157 ; 

 excessive transpiration, 64, 91, 

 92, 106, 137, 158-65, 203 ; 

 heat-rays, 64, 95, 102, 138 ; 

 injury, 92, 115, 142, 155; 

 intense light, 95, 102, no, in, 

 112, 199; parasites. 138, 142. 



Protection of embryos, 321. 332, 

 333, 373 ; of lateral roots, 72. 



Protective tissues, gi et scq.. 135 

 et seq. 



Proteins, 2, 7, 14, 40, 50-52, 53, 

 143, 262, 343 ; decomposition 

 oi. b^' Bacteria, 263 ; hvdrolv- 

 sis of, =,1 ; in latex. 135 ; re- 

 actions of, 3, 49 ; S()lul)le, 50 ; 

 translocation cif, 52, 88. 

 Proteolytic enzj-mes. 52, 33, 54, 



149. 

 Prothalhis of, Angiosperms, 373 ; 



