INDEX 
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. Bergianum, 460 
(Fig. 258); of elmeinthostachys, 460 (Fig. 
257). 
Stomata, functionless in Sphagnum, 274. 
Storage-tuber of Phylloglossum, 352. 
Strobili, symmetry of, 208. 
Strobilus, theory of, 132, 138, 248; of 
Equisetum, 370. 
Stromatopierts, 553. 
Struthiopterts, 631. 
Subtending position of bract, 695 (Fig. 361). 
Suppression, 162. 
Suspensor, its variability, 182; in Botrychium 
obliguum, 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); 
position of, 655 (Fig. 354). 
Tetrad-division, 49, 50 (Fig. 32), 87. 
Tetraspores, 66, 67, 68. 
Thallophytes, alternation in, 63. 
Tmesipterts, 144 (Fig. 73); 408 (Figs. 226, 
227, 228); spore-producing members of, 
413 (Figs. 230, 231); anatomy of, 419 
(Fig. 234); sporangiophore, 147 (Fig. 77); 
Tannensis, septum fertile, 99 (Fig. 58). 
phyletic 
727 
Todea, 530, sporangia of, 532 (Fig. 294), 
533 (Figs. 295, 296); anatomy of, 536 
(Fig. 298) ; seperba, 582. 
Trabeculae of Zsvetes, 95, 3183 of Lepido- 
Strobus, 323. 
Tradescantia, pollen grain of, 43 (Fig. 29). 
Trichomanes, habit, 575 (Fig. 323); sorus, 
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 Potonié, 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, 157. 
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) 5 529, Grayi, 499 (Fig. 270). 
GLASGOW ! PRINTED AT THE UNIVERSITY PRESS BY ROBERT MACLEHOSE AND co. LTD. 
