TABLE OF CONTENTS. Xlll 



PAGE 



spores first indicated by Morison, 257 ; Ehrhart's observation of the 

 two-lobed leaf preceding the perfect fern, 257; germination of spores 

 of ferns, first accurately observed by Kaulfuss, 257 ; sexual organs of 

 prothallium, discovered by Bischoff, 257, 258 ; antheridia and sper- 

 matozoids, discovered by Nageli, 258 ; Nageli's observation of the 

 archegonia, 258 ; real nature of the archegonia first ascertained by 

 Suminski, 258, 259; Wigand on the sexual organs of ferns, 259; 

 observations of Hofmeister confirmatory ^of Suminski's results, 260; 

 Schacht on the archegonia aud impregnation of ferns, 2G0, 261 ; 

 Von Mercklin on the same subject, and his observation of the 

 entrance of the spermatozoid into the archegonia, 261 ; Mettenius' 

 observations, 261 ; Henfry on the sexual reproduction of ferns, 261 ; 

 further statements by Hofmeister and Wigand on the same subject, 

 261,262; anatomy of fern-stem, first clearly explained by Von 

 Mohl, 262 ; Brogniart on the ramification of ferns, 262 ; his views, 

 supported by Hofmeister and Steuzel, 262 ; opposed by Karsten and 

 Mettenius, 263 ; views of Pringsheim and Irmisch adopted by Hof- 

 meister, 263 266. 



CHAPTER VIII. 



EaUISETACE^E 267 



{Equisetum arvense, pratense, variegatum, hyemale, palmtre, and limosmi.) 



Growth of the stem of Equisetum, 267 269; Cramer on cell-succession 

 in the end of the stem, 267, note; production of the leaf, 269, 270; 

 production of the teeth of the edge of the leaf, 270, 271 ; relation of 

 the cells of the pith to those of the outer layers of the stem, 271 

 273 ; formation of the epidermis, 273 ; differentiation of the vascular 

 bundles, 273 275; separation of the cells of the pith, 275 ; ramifica- 

 tion caused entirely by adventitious buds and their mode of growth, 

 275 278; formation of adventitious roots in Equiseta growing in 

 damp situations, 278 280 ; fructification of Equisetaceae, 280 288 ; 

 development of spore-mother-cells, 281 286 ; elaters, 287 289 ; 

 spores, 2S8 290; Sanio's observations on abnormal formation of 

 elaters, 291 ; evolution of the spores, 291, 292 ; formation of the pro- 

 thallium, 292, 293 ; male and female prothallia, 293 ; formation of 

 antheridia, 293, 294; spermatozoids, 294 296; obstacles to the 

 germination of Equisetacese, 296, 297; female prothallia, 297; Bis- 

 choff's observation of antheridia and archegonia on the same prothal- 

 lium of E. syloaticum, 297, note; observations on the production of 

 male and female prothallia, 297, 298 ; formation of archegonia, 298 

 300; impregnation, 300; development of the impregnated arche- 

 gonium, 300, 301 ; development of the embryo, 301 303; formation 

 of the stem, 303 ; development of adventitious buds, 303, 304. His- 

 torical Review : Observations of Vaucher and Agardh on the germina- 

 tion of the spores of Equisetacese, 304, 305 ; Bischoff's observations 

 on the same subject, 305, 306; first account of the antheridia given 

 by Thuret, 306 ; archegonia discovered by Bischoff, 306 ; observations 

 of Milde and Hofmeister on the sexual organs of Equisetacese, 306. 



