482 



GYMNOSPERMS 



Dacrydium, ovules, jo/ 



Dadoxylon, 168, 170 



Dates, pollination and fertilization, 313 



Dermatogen, 266, 270 



Dioecism, 99, 275 



Dioon, 62, 6 J, 64, y8; growth-rings, 82, 83; 



pits, 8^; rays, 86, 87; leaf trace, 87, go; 



girdling, 88, 8g; cone domes, go, gi; 



new crown, gj; strobilus, 106; seed, 



log, no 



Dorycordaites, 167 



Egg, in cycads, 125; haustoria, 125 



Embryo, Cycadofilicales, 39, 40; cycads, 

 I3g-4S; Coniferales, 342, 343-57 



Embryogeny, in cycads, J3g-4g; polarity, 

 140; evanescent segmentation, 143; 

 differentiation, 144-48 



Enceplialartos, 72, 73, 114, 122 



Eospermatopteris, 9 



Ephedra, 362, 363-81; stem, 36S; stro- 

 bilus, 36g; megaspore, 377; archegonia, 

 378; fertilization, 37g, 381; embryo, 

 3^1,382 



Epidermis, 261, 269 



Epimatium, 300, 301 



Euphorbia, 28 



Evanescent segmentation, 143 



Exine, in cycads, 128 



Female gametophyte, cycads, ///, 720- 

 26; Ginkgo, 206; Coniferales, 321, 322, 

 324, 327, 329, 333 



Fertilization, in cycads, 136, 137; Coni- 

 ferales, 331; Piniis, 337, 338; Torreya, 

 332; Abies, 33g; double, 341 



Fossil, record, 3, 4 



Free nuclear division, in cycads, 118, 120, 

 140-42; Ginkgo, 212; Coniferales, 

 Pinus, 322; Taxus, 324; Torreya, 332 



Gametophyte, female in cycads, ///, 118- 

 27; male in cycads, 127-37 



Generative cell, cycads, 128; Ginkgo, 207; 

 Coniferales, 308, 317 



Geological time, 3, 4 



Gigantism, 217 



Ginkgoales, 184; life-history, 186; stem, 



187, 188; gametophytes, 204-g; embryog- 

 eny, 211, 212, 213; seedling, 214; phy- 

 logeny, 214 



(iirdling, in cycads, 81 



(Jnetales 3O1 ; phylogeny, 429 



Gnelum, 408, 4og; histology, stem, 411; 

 root, 413; vessel, 414; strobilus, 413, 

 415; 416, 417, 418; ovule, 4ig; male 

 gametophyte, 420; female gameto- 

 phyte, 422; embryo, 424 



Growth-ring, 238, 2jp, 240 



Haustoria, of cycad egg, 125; of pfjllen 



tube, 129 

 Ileterangium, 24, 25 

 Heterospor)', 31 



Hybrids, in cycads, 152, 153, 154 

 Hypocotyl,27j 



Impressions, in stone, i 

 Inline, in cycads, 12S 



Juniperits monosperma, 235; J . communis, 

 2g2 



Jurassic, 4 



Juvenile leaves, 261, 262 



Kaloxylon, 8, 15 

 Keleleeria, 302 

 Kulm, 4 



Lagenostoma, 7 



Leaf, in cycads, 89, gi; Ginkgo, IQ3, ig4; 

 anatomy, ig^; venation, ig4; Coni- 

 ferales, 253, 254-62; histology, 263-66; 

 mosaic, 254 



Leaf traces, 13, 81, 89, go 

 Leaves, key, 92; juvenile, 95, g6; struc- 

 ture, g7 



Liassic, 4 



Ligule, 296, 297 



Lycopodium, 289 



Lyginodoidroti, 7 



Lyginopleris, 13, 14, 15, ig, 20, 21, 22, 23 



Macrozamia, 67, 68, 6g, 77 



Male gametophyte, cycads, 127, 128, 130- 



36; Ginkgo, 207; Coniferales, 306, 308; 



310-12; 317-20 



Medullary rays, cycads, 86, 87; Ginkgo, 



ig2; Coniferales, 241 

 Megaspore, cycads, ///; Coniferales, 



301, 304; Pinus, 321 

 Megaspore membrane, in Cycadofilicales, 



23; in cycads, 126; thickness, 325 

 Mcgasfwre mother-cell, in Ginkgo, 201; in 



Coniferales, 307, 303 



