INDEX 
Pseudosteles, 193. 
Psilotaceae, 398, 408. 
Psilotum, 88 (Fig. 45); sporangiophore, 
147; spore-producing members of, 416 
(Fig. 232); anatomy of, 418' (Fig. 233); 
408, 412 (Fig. 229). 
Pteridophyta, 288; balance of alternating 
generations, 36. 
Pteridosperms, their discovery, 496. 
fteris, phyletic position of, 655 (Fig. 354) ; 
elata, 616 (Fig. 342); heterophylla, 632. 
Pteropsida, 486. 
Pychocarpus, 511, §20 (Fig. 288); zaztus, 
151 (Fig. 84). 
Rachiopteris Oldhamia, 501. 
Radial construction, 201, 252. 
Radula, 264 (Fig. 125). 
Recapitulation, theory of, 173; applicable 
within limits, 185; exceptions to its 
applications, 159, 636, 660, 
Receptacle of sorus, 634; not a result of 
“*metamorphosis,”’ 635. 
Red Seaweeds, 67. 
Reduction, 233, 253; its prevalence in 
phyletic speculation, 235; of leaf, 139; 
in moss-sporogonia, 238; in Ophioderma, 
241; follows on seed-habit, 717; of chro- 
mosomes, 50 (Fig. 32); phyletic delay 
in, 77. . 
Reduction-series, synthetic necessity of, 482. 
Rhizophora, 96, 142 (Fig. 72). 
Rhizophores, of Selaginella, 219. 
Rhopalodia, 71 (Fig. 41). 
Riccia, 33, 34 (Fig. 17) ; absence of polarity, 
203; archegonium of, 257 (Fig. 118). 
Ricciocarpus, 34 (Figs. 18, 18a); sporo- 
gonium of, 257 (Figs. 119, 120). 
Riella, 263. 
Root of embryo, variable in time and place 
of origin, 671, 672; origin of, 216; 
exogenous, 219; capless, 219. 
Root-apex.of Osmundaceae, 649 (Fig. 351). 
Rootless sporophytes, 218. 
Roots, ‘‘ free-living,” 183. 
Root-structure in Ophioglossaceae, 458 (Fig. 
256), 489. 
Salvinia, 176, 610. 
Salviniaceae, 610; related to Gradatae, 611. 
Schizaea, 543 (Figs. 300, 301, 302); anatomy, 
549. 
Schizaeaceae, external characters, 542; spore- 
725: 
producing members, 544; anatomy, 547 ;. 
segmentation of sporangium, 547 (Fig. 
305); phyletic position of, 654 (Fig. 354). 
Schizoneura, 372 (Fig. 198). 
Schizostelic state, 192. 
Scolopendrium vulgare (Fig. 93); apogamy,. 
52, 54 (Figs. 34, 35). 
Scolecopteris, 511 (Fig. 282), 521 (Fig. 289) ;. 
polymorpha, 522 (Fig. 289). 
Secondary thickening, 690; in Lepédoden- 
dron, 334; in Ophioglossaceae, 488. 
Seed-habit, 703, 716; often leads to re- 
duction, 705. 
Seed-plants, balance of alternating genera-. 
tions, 43. 
Segmentation, 176; of embryo, 179; of 
zygote in Lycopods, 345. 
Selaginella, origin of sporangium, 146 (Fig.. 
74); symmetry of, 211. 
Selaginalla apus, microsporangium of, 39: 
(Fig. 23); megasporangium of, qo (Fig. 
24); microspore of, 40 (Figs. 25, 26). 
Selaginella sanguinolenta, 299; Martensii,. 
299; apus, 317; repestris, 317; helvetica, 
316; Wallichit, 316; Kraussiana, 316 ;. 
tnaequalijolia, 334; Willdonovir, 3343 
laevigata, 334; spinulosa, 299 (Fig. 51);. 
basal knot of, 220 (Fig. 113); general 
morphology of, 300 (Figs. 148, 149); 
sporangia of, 316 (Figs. 163, 164); anatomy - 
of, 332 (Fig. 173); embryology of, 356- 
(Fig. 190). 
“* Selago”’ condition, 164; in Lycopods, 
164; in /soetes, 165; in Psilotaceae, 165 ;. 
in Ophioglossaceae, 166 ; in-Ferns, 167. 
Senftenbergia, 546 (Fig. 303); Ophioder- 
matica, 522 (Fig. 289). 
Septa, origin of, 97, 110. 
Septum in 7yesipterts, 411, 415. 
Series of progression, 10; of reduction, Io. 
Sexual cycle, 75. 
Sexuality, a constantly recurring feature, 9. 
Sigillaria, stelar structure, 231; fructifi- 
cations of, 325; elongata, 337; elegans, 
3373; Menard?, 337 ; spinulosa, 337. 
Sigillariostrobus Crepint, 325. 
Simplices, 117, 497, 498, 634. 
Small-leaved types primitive, 139. 
Solenostelar structure, of Gletchenta, 562: 
(Fig. 313)3 of AZatonta, 569 (Fig. 319); 
of Loxsoma, 573 (Fig. 321); of Denn- 
staedtiinae, 600 (Fig. 333); of Preris, 616- 
(Fig. 342). 
