726 
Solenostele, 190; in Ferns, 647. 
Somatic expansion, 77. 
Soral state in Ferns, 633. 
Sorus, a sporangiophore, 151; fission of, 
6333; primitive position of, 633; shifting 
of position of, 636; extension of, in 
Ferns, 699. 
Speculative morphology, 6. 
Spencerites, 146 (Fig. 76); ¢nsignzs, 321 
(Fig. 167). 
Spermatozoids, fertilisation by, 2, 244. 
Sphaerocarpus, 92, 263. 
Sphaeropteris, 617. 
‘Sphagnales, 272. 
Sphagnum, 93 (Fig. 48), 272 (Fig. 132). 
Sphenophyllum, vegetative system, 399; 
anatomy, 400; strobilus, 401. 
‘Sphenophyllales, 398 ; summary for, 423. 
Sphenophylleae, 230, 398. 
Sphenophyllum cuneifolium, 400 (Fig. 216) 
(=S. Dawsonz), 402, 425 (Fig. 219); 
S. tenerrimum, 400 (Fig. 216); S. verti- 
cillatum, 400 (Fig. 216); majus, 147 
(Fig. 78); zzsigne, goo (Fig. 217); S. 
trichomatosum, 402 (Fig. 218); S. angusti- 
folium, 4023 tenerrimum, 402; Romerz, 
402, 425 (Fig. 220); majus, 402, 424 
(Figs. 221, 222); fertz/e, 404. 
Splachnum, 281 (Fig. 138); luteum, 203 
(Fig. 102). 
Sporangia, 693 ; positions of, 694 (Fig. 360) ; 
increase and decrease of, 86; uniformity 
of dimensions of, 114; indefiniteness of 
number, 115; relation to axis, 115; in- 
dividual identity of, 117; simultaneous 
or successive, I175; variations in number 
-of, 119, 129, 249; increase in number of, 
120, 249 ; decrease in number of, 120, 249; 
septation of, 120, 249; interpolation of, 
120, 121, 2493 interpolation restricted to 
certain groups, 130; fusion of, 120, 126, 
130, 249; abortion of, 120, 127, 161, 249. 
‘Sporangiophore, 144, 250, 693; of 7mesip- 
tevts, 409, 410, 414; of Pszlotum, 412, 
416 ; number of sporangia, 425 ; position, 
425; development, 426; a part suz generis, 
153, 426; amplification of, 699; positions of, 
604 (Fig. 360); of Helmdnthostachys, origin 
of, 455 (Figs. 254, 255); of Zgzdsetum, 
371, 377, 3793 morphology of, 382. 
Sporangiophoric Pteridophytes, 366; sum- 
mary for, 423; a brush of related phyletic 
lines, 712-714. 
INDEX 
Sporangium defined, 103, 112; individuality 
of, 110; septation of, 110; of Ferns, 
segmentation of, 637 (Fig. 349); stalk of, 
638 ; head of, 638 ; annulus of, 638 ; pluri- 
seriate annulus, 639; contents of, 641; 
succession of, 644 ; of Filicales, 637. 
Sporangiogenic band, 447, 449 (Figs. 247, 
248). 
Spore-enumerations, 641; variation in num- 
ber in near affinities, 643; in Botryopteri- 
deae, 502; in Marattiaceae, 516, 520; in 
Osmundaceae, 536; in Schizaeaceae, 547. 
Spore-output of Male Fern, 23. 
Spore-producing members, 693; of Filicales, 
632. 
Spore-production a constantly 
event, 9. 
Spores, dispersal of, 645 ; in Simplices, 645 ; 
in Gradatae, 646 (Fig. 350); in Mixtae, 
646. 
Sporogonia, symmetry of, 203; of Mosses, 
general comparison of, 285. 
Sporogenous group, 87; tissue, segregation 
of, 85; hypodermal origin of, 109; not 
strictly circumscribed, 112; time of dis- 
tinctive development, 116; disintegration 
of, 142. 
Sporophyll converted to foliage leaf (Goebel), 
171; of Zmestpteris, 409, 410, 4143 of 
Psilotum, 411, 416. 
Sporophyte, 32. 
Sporophytic budding, 20, 61. 
Sporophylls, 144. 
Spross-glied-lehre of Celakovsky, 135. 
Stachannularia, 377. 
Stauropteris oldhamia spores germinate in 
sporangium, 497, 498 (Fig. 271), 501. 
Stigmarian trunks, 220 (Fig. 112); 302 
(Fig. 150). 
Stegocarpae, 277. 
Stelar theory, 189. 
Stele, 189; non-medullated monostele pri- 
mitive, 685; medullation, 687; disinte- 
gration, 687 ; xylem-sponge of Lycopods, 
688; intrusion of outer tissues leads to 
solenostele, 688; of Lycopods, 328; of 
Selaginella, 332 (Fig. 173); of Lepidoden- 
dron, 333 (Fig. 174). 
Stem-apex of Angiopterts and Osmunda, 650 
(Fig. 352). 
Sterile and fertile regions, their relations, 
156, 251. 
Sterile region secondary, 161. 
recurring 
