INDEX 



477 



Pits: absence of tangential, in Cordaitales 

 and other ancient gymnosperms, 27; 

 bordered, 6, 7; condition of, in heart- 

 wood, 56; half bordered, 7 ; radial, 27; 

 simple, 3, 5, 6, 7; tangential, 27 



Pitting, distribution of, 27, 428 



Pityoxylon, structure of, 349 



Plastid, 2 



Plates, photographic, 463, 466 



Podocarpineae, 343 



Pollen chamber, 226, 227 



Polydesmy in Cycadales and Gnetales, 364 



Porous perforation in vessels, origin of, 101 



Potentilla, origin of herbaceous type in, 

 187 



Prepinus: leaf of, 207, 331; relation of, 

 to Cordaitales, 332 



Preservation of material, 444 



Primary wood, degeneracy of, 169 



Principes, anatomy of, 196, 413 



Proangiosperms, 303 



Protocalamites, 268 



Protoplasm, i 



Protostele, 162, 278; collateral, 165; con- 

 centric, 162; in Filicales, 278 



Protoxylem, 18, 19, 20, 21 



Psilotum, 253 



Pteris: bundle of, 21, 108; development 

 of stem in, 280, 282; phloem of, 109; 

 rhizome of, 9, 10, 132; vessels of, 92 



Pteropsida, 244, 247; geological range of , 

 249; megaphylly of, 249 



Quercus: fiber tracheids of, 31; stem of, 

 179, 404; tracheids of, 31; vessels of, 

 99; wood of, 15; wood rays of, 76, 

 178, 181. 



R 



Ranales, characteristics of, 386 



Rays: aggregate, 78, 82; compound, 78, 

 82; fusiform, 69, 74; linear, 69; 

 marginal cells of, 69; medullary, so 

 called, 61; origin of, in Coniferales, 68, 

 72, in Lepidodendron, 62, 63, 64; rela- 

 tion of, to resin canals, 70; tracheids 

 of, in Lepidodendron, 62, 64; types of, 

 in Casuarina, 77; uniseriate, 67, 69; 

 width of, in Cordaitales, 66, in Cyca- 

 dales, 75, in Cycadofilicales, 65 



Recapitulation: in Coniferales, 235; in 

 first annual ring, 237; in oaks, 235; in 

 Phyllocladus , 235 



Resin canals, relation of, to resin cells, 343 



Reversion, 72, 73, 74, 75, 241 



Rhizophore, 262 



Rhodotypus, fibers and tracheids of, 33 



Robinia Pseudacacia, mucilaginous fibers 

 of, 34 



Root: absence of medulla in, 173; defini- 

 tion of, 137; development of, 145; 

 exarch primary structure of, 145; 

 exodermis of, 158; in Coniferales, 145; 

 in dicotyledons, 151; in herbaceous 

 dicotyledons, 156; in Lycopodium, 143; 

 in monocotyledons, 159; in Osmunda, 

 150; piliferous layer of, 158; primary 

 and secondary structure of, 138; pri- 

 mary wood of, 145, 150, 151, 157, 

 159; radial organization of, 143; rays 

 in, 147; spiral tracheids in, 161; 

 velamen of, 159 



Root cap or pileorhiza, 138 



Root hairs, 146, 150, 158 



Sachs, erroneous views of, as to origin 

 of stem, 191, 406 



Safe lights, 466 



Safranin, 458 



Salvia, origin of herbaceous type in, 189 



Sapwood or alburnum, 55 



Scalariform perforation of vessels, origin 

 of, 97 



Scolymus, oil canals in root of, 441 



Scorzonera: laticiferous system of, 435; 

 oil canals of, in root, 441 



Secondary wood as indicator of climatic 

 conditions, 418 



Sectioning of material, 454 



Seed: in angiosperms, chalazogamous, 

 230; in Archigymnospermae, 226; in 

 Casuarina, 231; in dicotyledons, 232; 

 in monocotyledons, 231; in Pinus, 

 233; of Coniferales, 229; of Cycadales, 

 226; of Ginkgo, 228; of porogamous 

 angiosperms, 230 



Seedlike rnegasporangia, 223, 225 



Selaginella, 216, 225, 254 



Sequoia: anatomy of, 339; cone axis of, 

 340; marginal tracheids of, 73, 341; 

 parenchyma of, 339; tracheids of, 25; 

 wound canals of, 341 



Sharpening of knives, 453 



Shutter, photomicrographic, 465 



Sieve plates: in the angiosperms, 120, 

 123; in gymnosperms, 114; in her- 

 baceous angiosperms, 125 



