XVI TABLE OF CONTENTS. 



PAGE 



unequal development of the forks of the stem in some species, 381 ; 

 their equal development in others, 381, 382 ; structure of the stem, 



382, 383 ; production of adventitious roots from the forks of the stem, 



383, 384; production of new plants from fragments of the stem of 

 Selaginella, 384; fructiferous shoots of Selaginella, 384, 385 ; produc- 

 tion of the sporangia, 385 — 392 ; views of Bischoff and Von Mold on the 

 nature of the sporangia of Selaginella, 3S7 ; differentiation of the 

 macrosporangia and microsporangia, 387 ; development of the macro- 

 sporangia, 387 — 389 ; production of the macrospores, 388 — 390 ; 

 differences in certain species, 389, 390; development of the micro- 

 spores ; formation of rudiments of prothallia from macrospores before 

 the bursting of the macrosporangia, 391, 392; Metteuius on the de- 

 velopment of the cells of the prothallium, 392, note ; uncertainty as to 

 the first stages of development of the prothallium, 392, 393 ; dormancy 

 of the macrospores of Selaginella hortensis and S. Helvetica, 393 ; 

 germination of macrospores, 393 ; formation of archegonia, 393, 394 ; 

 production of spermatozoids from the microspores, 394, 395 ; cause 

 of want of success in experiments on sowing spores of Selaginellce, 

 295 ; only one archegonium usually impregnated on the prothallium, 

 395 ; development of the pro-embryo, 395, 396 ; development of 

 the embryo, 396, 397 ; greater resemblance of Lycopodium in its mode 

 of growth to Polypodiacese than to Selaginella, 398 ; growth of Psilo- 

 turn triquetrum, 398 ; remarks on the reproduction of Lycopodiacese 

 with spores of only one kind, 398, 399 ; De Bary's observations on 

 the spores of Lycopodium mundatum, 399. Historical review : — 399. 



CHAPTER XV. 



CONIFERS ...... 400 



Structure of the ovules of Coniferse, 400, 401 ; development of the pollen 

 of the Coniferse, 401 — 406 ; peculiar cell-inultiplicatiou in the free 

 pollen-cells of Coniferae, 404, 405 ; structure of the pollen of the 

 Abietinese explained by Fritzsche and Schacht, 405, note ; passage of 

 the pollen through the micropyle of the ovule to the nucleus and 

 formation of pollen-tubes, 406 ; resemblance of the pollen of Ephedra 

 to that of Larix, 406, note; development of the endosperm, 406 — 

 409 ; development of the endosperm in Taxus, 409, 410 ; production 

 of the corpusculum in Coniferae, 410 — 414; statements of Mirbel and 

 Spach as to the contents of the corpuscula, 414 ; development of the 

 endosperm of Coniferse not always dependent on the contact of pollen 

 of the same species, 414, 415 ; second penetration of the pollen-tube 

 towards the embryo-sac, 415 — 421 ; development of free spherical cells 

 in the ends of the pollen-tubes which reach or enter the corpusculum, 

 416 ; penetration of the pollen-tube into the corpusculum in Pinus 

 sylvestris, 417, 418 ; in Pinus Abies, L. (Abies excelsd), 418, 419 ; in 

 Pinus Larix, 419, 420 ; relation of the pollen-tube to the corpuscu- 

 lum, 421 ; development of the embryo, 421 — 432 ; evolution of the 

 impregnated germinal vesicle, 421, 422 ; Schacht ou this subject, and 

 Geleznoff on the formation of the embryo in Larix, 422, note ; rela- 

 tion of the pollen-tube to the endosperm in Taxus baccata, 422 ; de- 

 velopment of impregnated germinal vesicle in that species, 423 ; im- 



