INDEX 



727 



Sterilisation, 84, 87, 161, 246; in Pterido- 

 phyta, 89, 93 ; in Bryophyta, 90 ; in 

 Seed-Plants, 96, 97 (Fig. 57) ; in Mar- 

 chantiales, 263 ; in Jungermanniales, 267; 

 in Anthocerotales, 269 ; in Hepaticae 

 generally, 271; in Mosses, 286; in 

 Bryophytes, 660. 



Stock of Ophioglossaceae, structure of, 459, 

 etc. (Fig. 236) ; of O. fiergianum, 460 

 (Fig. 258) ; of Hdminthostachys, 460 (Fig. 



257). " 



Stomata, functionlcss in Sphagnum, 274. 

 Storage-tuber of Phylloglossum, 352. 

 Strobili, symmetry of, 208. 

 Strobilus, theory of, 132, 138, 248; of 



Equisetuni) 370. 

 Stromatopteris, 553. 

 Stnithiopteris, 631. 



Subtending position of bract, 695 (Fig. 361). 

 Suppression, 162. 

 Suspensor, its variability, 182; in Botrychium 



obliquum, 472 (Figs. 264-266) ; present or 



absent, 675. 

 Symmetry, 201, 252; radial primitive for 



sporophyte, 203, 217, 252. 

 Synangia, in Botrychium Lunaria, 453 (Fig. 



252) ; in Botrychium daucifolium, 454 



(Fig. 253); of Marattiaceae, 512. 

 Synapsis, 50 (Fig. 32). 

 Synthetic types, 230. 



Tapetum, 104. 



Thyrsopterideae, 589. 



Thyrsopteris, 589 (Fig. 329); phyletic 

 position of, 655 (Fig. 354). 



Tetrad-division, 49, 50 (Fig. 32), 87. 



Tetraspores, 66, 67, 68. 



Thallophytes, alternation in, 63. 



Tmesipteris, 144 (Fig. 73) ; 408 (Figs. 226, 

 227, 228) ; spore-producing members of, 

 413 (Figs. 230, 231); anatomy of, 419 

 (Fig. 234); sporangiophore, 147 (Pig. 77); 

 Tannensis, septum fertile, 99 (Fig. 58). 



Todea, 530, sporangia of, 532 (Fig. 294), 

 533 (Figs. 295, 296) ; anatomy of, 536 

 (Fig. 298) ; superba, 582. 



Trabeculae of hoetes, 95, 318 ; of Lepido- 

 strobus, 323. 



Tradesfantia % pollen grain of, 43 (Fig. 29). 



Trichomanes, habit, 575 (Fig. 323) ; soius, 

 578 (Fig. 324) ; sporangia, 579 (Figs. 325, 

 327) ; spore enumerations, 580 ; filmy 

 structure, 582; stock, 584; $Feea, 631: 

 alatum, apogamy and apospory, 56. 



Tubicaulis, 501. 



Uebergipfelung theory of Potonie, 135. 

 Ulex seedlings, 185. 

 Ulothrix, 73. 

 Uredineae, 69. 



Vaccinium Myrtillus, symmetry of, 209. 

 Radial type of early Ferns, 625. 

 Vascular shoot, symmetry of, 206. 

 Vascular skeleton, 685. 

 Vaucheria, 64. 

 Vegetatio languescens, 1 5 J- 

 Vegetative region of Pteridophytes, sym- 

 metry of, 209. 

 Velum, origin of, 319. 

 Venation in Ophioglossaceae, 463. 

 Ventral lobe, 153, 426, 481. 



Water-relation, 2. 



Welwitschia, floral symmetry, 208. 

 Whorled leaves, probably primitive, 711. 

 Wings of leaf in Ferns, comparative study 

 of, 651 (Fig. 359). 



Woodsia, 617- 

 Working hypothesis, summary of, 244. 



Xylem-core, 334. 

 Xylem-islands, 330. 

 Xylem-sponge in Lycopodium, 330. 



Zygopteris, 585, sporangia of, 501, 508 (Fig. 

 272) ; 529, Grayi, 499 (Fig. 270). 



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