CHAPTER VIII 



A 



'- sp 



PTERIDOPHYTA (FERNS) 



IN most Bryophytes the gametophyte is the predominant phase, 

 and the sporophy te is relatively unimportant ; in Anthoceros and 

 some Mosses, however, the sporophyte is large and develops a com- 

 plex system of assimilating tissue, so that it becomes almost inde- 

 pendent. In no Bryophytes, however, does the sporophyte develop 

 roots. In the Pteridophytes, or Ferns, and their allies, the sporo- 

 phyte early develops a root 

 which puts it into communi- 

 cation with the earth, and it 

 thus becomes quite inde- 

 pendent of the gametophyte. 



With the increasing im- 

 portance of the sporophyte, 

 which is always a leafy plant, 

 often of large size, there is 

 a reduction of the gameto- 

 phyte, which in the most 

 specialized Pteridophytes 

 may be reduced to a few 

 cells, completing its whole 

 development within twenty- 

 four hours, or less. 



In most Pteridophytes the 

 gametophyte (called the 

 "PrnrhalHiiTYi "^ is a small 

 plant closely resembling the 

 Simpler thallose Liverworts. 



Tn Pxppntinnal rasps ir mav 

 ma y 



reach a length of several 

 centimetres and live for several months, or even years (Fig. 205). 

 In certain forms, e.g. Botrychium, Lycopodium clavatum, it is a sub- 

 terranean, tuberous body, quite destitute of chlorophyll, and living 

 as a saprophyte. 



Budding of Gametophyte. Where the gametophyte is large and 

 long-lived, it not infrequently multiplies by the formation of special 

 R 241 



- g 



Via. 2D&. A, B, Marattia Dougltuii. A, old 

 gametophyte, the apex divided dichoto- 

 mously, and with lateral buds, A; (X 2). B, 

 gametophyte with young sporophyte, sp, 

 attached. C, Anthoceros fusiformis. Gam- 

 etophyte, 5-, with four sporophytes attached, 

 sp. (Natural size.) 



