FERNS. 



26l 



here one has an opportunity during the winter season not only to observe these 

 interesting plants, but also to obtain material for study. In the tree ferns 

 which often are seen growing in such places we see examples of the massive 

 trunks and leaves of some of the tropical species. 



547. The fern plant is a sporophyte. We have now studied 

 the fern plant, as we call it, and we have found it to represent 

 the spore-bearing phase of the plant, that is the sporophyte (cor- 

 responding to the sporogoniurn of the liverworts and mosses). 



548. Is there a ga- 

 in etophyte phase in 

 ferns? But in the spor- 

 ophyte of the fern, which 

 we should not forget is 

 the fern plant, we have 

 a striking advance upon 

 the sporophyte of the 

 liverworts and mosses. 

 In the latter plants the 

 sporophyte remained 

 attached to the gameto- 

 phyte, and derived its 

 nourishment from it. 

 In the ferns, as we see, 

 the sporophyte has a 

 root of its own, and is 

 attached to the soil. 

 Through the aid of root 



hairs of its own it takes up mineral solutions. It possesses also 

 a true stem, and true leaves in which carbon conversion takes 

 place. It is able to live independently, then. Does a gametophyte 

 phase exist among the ferns ? Or has it been lost ? If it does 

 exist, what is it like, and where does it grow ? From what we 

 have already learned we should expect to find the gametophyte 

 begin with the germination of the spores which are developed 

 on the sporophyte, that is on the fern plant itself. We should 

 investigate this and see. 



Fig. 296. 

 Bulbil growing from leaf of asplenium (A , bulbiferum). 



