THE LIFE-HISTORY OF A FERN 



[CH. 



These are the salient features in the life-cycle of a Fern as it is seen in 

 its simplest form. They may be represented graphically to the eye in a 

 diagram (Fig. 28). The two most notable points are those where the indi- 



Fig. 25. Embryo of Adiaiitum concinnum in the enlarged venter of 

 the archegonium, so far advanced as to show the parts of the 

 embryo. The epibasal hemisphere is to the left, the hypobasal to 

 the right. Z = leaf or cotyledon. R—xoot. 3'=stem. 7^=foot. 

 (After Atkinson.) 



Fig. 26. Adiaiitum Capillus Veneris. 

 The prothallus,//, seen from below 

 has a young Fern- Plant attached to 

 it. /^ = first leaf, w, te/' = first and 

 second roots. A = rhizoids of the 

 prothallus. ( x about 30.) (After 

 .Sachs.) 



Fig. 27. Adiaiititiii Capillus Veneris. Longi- 

 tudinal section through the prothallus, //, 

 and young Fern-Plant E. h — xoo\. hairs of 

 prothallus. a = archegonia. /5 = the first leaf. 

 7c; = the first root of the embryo. ( x 10.) 

 (After Sachs.) 



vidual is represented only by a single cell, viz. the spore, and the zygote. 

 These are two landmarks between which intervene two more extensive 

 developments, on the one hand the sexual generation or prothallus, on the 



