XVI CONTENTS. 



CHAPTER XXV. 



FERNS. 



The Christmas fern, 346. Fruit dots, 347. Sporangia, 348. 

 Structure of a sporangium, 349. Opening of the sporan- 

 gium and dispersion of the spores, 351. How does the 

 opening and snapping of the sporangium take place? 352. 

 The movement of the sporangium can take place in old and 

 dried material, 354. The common polopody, 356. Other 

 ferns, 357. Opening of the leaves of ferns, 358. Longevity 

 of ferns, 359. Budding of ferns, 360. The fern plant is a 

 sporophyte, 363. Is there a gametophyte phase in ferns? 

 364 page 165 



CHAPTER XXVI. 



FERNS (concluded}. 



Gametophyte of ferns, 365. Sexual stage of ferns, 365. Spores, 

 367. Germination of the spores, 368. Protonema, 369. 

 Prothallium, 370. Sexual organs of ferns, 371. Antheridia, 

 372. Archegonia, 373. Sporophyte, 374. Embryo, 374. 

 Comparison of ferns with liverworts and mosses, 375 ..page 176 



CHAPTER XXVII. 



HORSETAILS. 



The field equisetum, 380. Fertile shoot, 380. Sporangia, 381. 

 Spores, 382. Sterile shoot of the common horsetail, 383. 

 The scouring rush or shave grass, 384. Gametophyte of 

 equisetum, 385 page 187 



CHAPTER XXVIII. 



CLUB MOSSES. 



The clavate lycopodium, 387. Fruiting spike of Lycopodium 

 clavatum, 388. Lycopodium lucidulum, 389. Bulbils on 

 Lycopodium lucidulum, 390. The little club mosses, 392. 

 Sporangia, macrospores and microspores, 393. Male pro- 

 thallia, 394. Female prothallia, 395. Embryo, 396 page 191 



