376 



EMBRYOGENESIS IN PLANTS 



Pilularia globulifera, Fig. 36; 155 



Pinaceae, 190 



Pirns, Fig. 37; 171, 172, 174, 177, 190, 



191, 192, 193, 195, 196, 323; P. 



banksiam. Fig. 42; 192, 193; P. 



contorta, 193; P. laricio. Fig. 43; 



P. lambertiana, 193; Fig. 37; P. 



montana, 192, 195; P. nigra. Fig. 37; 



P. ponderosa, 194; Fig. 37; P. 



radiata, 195; Fig. 37; P. sabiniana, 



193 

 Piperad type, 236, 240, 255 

 Pisum, 238, 258, 310; P. sativum. Fig. 64 

 Plagiochasma, 68 

 Plagiochila, Fig. 16 

 Plantago lanceolata, 261 ; Fig. 66 

 plerome, 236 

 Plocamium, 60 

 Plumbagella, 224 

 Plumbago, 224 

 plumule, 261, 276, 281 

 Poa, 242, 270; P. atmua. Figs. 1, 71 

 Podocarpaceae, 205 

 Podocarpus, 205, 208, 209, 214; Fig. 49; 



P. halli. Fig. 48; P. macwphyllus 



maki, 209; P. totaira. Figs. 47, 48; 



P. urbanii, 209; Fig. 48 

 Poiteau, 272 

 polar nuclei, 224, 225 

 polarised development, suppressed by 



chemical treatment, 65 

 polarity, 6, 7, 13, 14, 15, 16, 17, 36, 37, 



46, 48, 51, 52, 61, 62, 66, 74, 77, 81, 



85, 88, 93, 108, 130, 142, 152, 160, 



166, 167, 168, 175, 177, 178, 186, 190, 



197, 198, 220, 224, 225, 228, 286, 288, 

 291, 317, 318, 320, 321; factors 

 determining, 17, 18; Fig. 3; effects 

 of centrifuging and ultra-centrifuging, 

 19; effect of light on, 121; effect of 

 gravity on, 24 



Polemonium, 242 

 poles, 7 



pollen tube, 172 



polycotyledony, 193, 256, 264; in- 

 duction of, 309 

 polyembryony, 174, 183, 189, 191, 195, 



198, 200, 204, 209, 212, 214, 218, 219, 

 221, 281, 286, 289, 291, 292, 293; 

 simple, 191; cleavage, 191; evolu- 

 tionary steps in, 192 



Polygonaceae, 292 



Polygonum, llA 



polyphyletic origin of monocotyledons, 



267, 268 

 polyploidy, 88 



Polypodiaceae, 149, 150, 155, 185 

 Poh podium aureum, 160; P. vulgare, 147 

 Polysiphonia, 9, 60, 61 ; P. atrorubescens, 



14; Fig. 2; P. nigrescens, Fig. 12 

 Polytrichum, 64 

 Populus, 255 



Porella bolanderi. Fig. 15; 73 

 position and nutrition, 29 

 Potentilla, 248; P. aurea. Figs. 60, 81 

 Poterium sanguisorba. Fig. 61 

 precocity, 163, 166, 169, 245 

 preformation, 38 

 Preissia, 68 



prevascular tissue, 146; origin of, 38 

 primitive seed plants, 107 

 'primitive spindle,' 9, 13, 188 

 primitiveness, 83, 100, 102, 103, 168, 



180, 193, 195, 245, 252, 254; in 



angiosperms, 252 

 Primula polyantha, 10 

 principle of discontinuity, 3 

 principle of minimal areas, 28 

 principle of precocity, 245 

 principles of embryogenesis, 329 

 Pringsheim, 144 

 procambial strands, 186 

 proembryo, 178, 180, 182, 186, 188, 190, 



191, 195, 197 

 propagules, 286 

 prophyll, 272, 277 

 prosuspensor, 198 

 Protea lepidocarpon, 257 

 protection of embryo, 73 

 proteins, 107, 176, 177, 190, 296, 297; 



synthesis of, 122, 322 

 protenema, 64, 77 

 prothallial tube, 210, 219 

 protocorm, 93, 96, 98, 100, 101, 102, 



103, 106 

 protophyll, 96, 98, 100, 101 

 protoplasm, fine structure of, 52 

 protoplasmic organisation, 319, 320, 



323 

 proto-pteridophytes. 171 

 Protosiphon, 41 ; Fig. 8 

 protostele, 141, 146, 164, 184 

 Prunus, 301 

 pseudoembryos, 299 



