210 PRACTICAL BOTANY. 



mucilaginous mass projecting from the open archegonium, they 

 pass through this and down the neck of the archegonium, and 

 finally coalesce with the oosphere. 



C.TffE YOUNG SPOROPHORE, OR FERN PLANT. 



V. The result of the process of fertilisation of the 

 oosphore of the archegonium by the antherozoids is 

 the development of a new Fern plant, or Sporophore, 

 and in cultures which have been continued for some 

 months such young Fern plants may be clearly seen 

 attached to the prothalli, but one prothallus produces 

 only one young Fern plant. 



Select a prothallus to which a young Fern plant is 

 thus attached, and wash from it the soil which adheres 

 to it. Examine it with a lens, and observe 



1. That the prothallus itself is similar in form and 

 structure to those before observed. 



2. That the young Fern plant is firmly attached to its 

 under surface by a lateral protrusion (Foot). 



3. That the young Fern plant consists of the following 

 parts : 



a. A Root which turns downwards into the soil. 



b. A lateral protrusion, the Foot, which maintains 

 a close physiological connection between the prothallus 

 and the Fern plant. 



c. A first leaf, or Cotyledon, with an elongated 

 petiole, and bifurcating, expanded, upper part: this 

 usually grows upwards through the depression at the 

 apex of the prothallus. 



d. Between the base of the cotyledon and the foot is 

 the Apex of the stem, which continues its growth, 

 and produces new leaves. 



