INI) 



457 



megasporan^ium jjO; nicj^aspore 2j^; 

 microsporangium 24 j, 2^2; micro- 

 spore 2^4; ovule 24 j, 2j4; secondary 

 wood section 229; seed joo; strobilus 

 2jS, 24j, 246, 2j2; ventral canal cell 

 266, 267 



Pitys 168 



Pityoxylon 304 



IMalysperms 42 



Podocarpineae 313; archcgonium 331; 

 male gametophyte 339, 340, 342 



Podocarpus, habit J14; leaf jiS; male 

 gamctophyte 34 1; strobilus 324 



Polycotyledony 297 



Polystele 5. <S 



Poroxylon, stem ibb 



Prepinus 304, 30S 



Primofilices 54 



Proangiosperms 75 



Proanthostrobilus 74 



Proembryo. Ephedra 3gj; Pinaceae 288, 

 2Sg, 2go, 2gi, 2g2, 2g3, 2g4; Taxaceae 



346. 347^ 349 

 Prothallial tissue, Pinaceae 277, 276'; 



Podocarpineae 339 

 Proto itj's 20 



Protostele 4; Gleichenia 5 

 Pseudotsuga, habit 223 

 Pteridophytes, vascular anatomy 4 

 Pteridostrobilus 75 

 Pteris, polystele 8 



R 

 Rachiopteris 13 

 Radiosperms 42 

 Resin canal, Pinaceae 2t,t, 

 Retinospora 225 

 Root, Cycadales 112, 113 



Saxegothaea, male gametophyte 341; 

 ovule 32 y 



Sciadopitys, proembryo 2g2 



Seed, Cycadofilicales 31, 32, 33, 34, 3s, 

 3^1 3^! 39, 40; paleozoic 42; Pinaceae 

 300; Stephanospermum 42, 43; Tax- 

 aceae 325; Torreya 2,3,^, 333 



Seedling, Cj-cadales 98, gg, 100, loi, 

 102, 103, 104, lOj, 106; evolutionary 



tendencies 427; Ciinkgoales 188, iqo: 

 Pinaceae 231; Welwitschia 3gg 



Sequoia, habit 224; megaspore 2j6; 

 proembryo 292 



Siphonoslele 4; amphiphloic 5, 6; 

 cladosiphonic 9; ectophloic 5, 7; 

 phyllosii)honic 9 



Solenostelc 5 



Sperm, Cycadales 14J, 146, 14J; evolu- 

 tionary tendencies 423 



Sphacrostoma 2)7 



Sphenopteris 22 



Spicular cells, Welwitschia jdp 



Stamen, Cordaitales 174; evolutionar\' 

 tendencies 415; Ginkgoales igi, ig2, 

 ig3; Gnetales 371, 380; Pinaceae 

 241; Taxaceae 319 



Stangeria, megaspore 127; megasporo- 

 phyll 130; microsporangium 119 



Stauropteris 30 



Stephanospermum 42, 43; microspore 



49, 50 



Strobilus, Bennettitales 72, 73, 76, 7g, 

 80, Si, 82; Cordaitales 172, 173, 17 j; 

 Cycadales 114, 122, 123, 12 j; evolu- 

 tionary tendencies 413; Ginkgoales 

 190, igi, ig2, 193, 195. ig6, ig7, igS; 

 Gnetales 370, 372, 374, 375, 376, 380; 

 Pinaceae 23S, 239, 240, 244, 246, 247, 

 2j2; Taxaceae 319, 320, 321, 322, 

 323, 324 



Suspensor, Pinaceae 295; Taxaceae 348, 



349 

 Sutcliffia 20 

 Synangium, Cycadeoidea 78 



Taxaceae 220; archegonium 330; chro- 

 mosomes 329; distribution 349; em- 

 bryo 346, 347, 348, 349; female game- 

 tophyte 329, 330, 337; fertilization 

 344, 345; history 349; leaf 317, 31S; 

 megasporangium 321, 327; megaspore 

 membrane 332; microsporangium 319; 

 relationship 350; stamen 319; stro- 

 bilus 319, 320, 321, 322, 323, 324; 

 vascular anatomy 315; vegetative 

 organs 315 



