444 



BOTANY 



the prothallus. The antheridium encloses a large spherical mass of sper- 

 matozoid mother-cells which are set free when mature by the swelling of the 

 contents and the breaking down of one of the central cells of the wall. The 

 spermatozoids have a spirally wound body and numerous cilia ; a small vesicle 

 is adherent to the spermatozoid (Fig. 404 JE). The antheridia originate from 

 single superficial cells (Fig. 404 A - C), as do also the archegonia (Fig. 405 



ad 



B 



C 



FIG. 403. A, Jiotrychium lunaria. Sporophyte. (J nat. size.) S, Ophwglossum vulgatum. Sporo- 

 phyte showing the bud for the succeeding year, (i nat. size.) C, Ophioglossum vulgatum. 

 Prothallus. an, antheridia; ar, archegonia; k, ,young plant with the first root; ad, ad- 

 ventitious branch ; h, fungal hyphae. (x 15 ; after BRUCHMANX.) 



A-G). The slightly projecting neck of the latter opens after the neck-canal-cell 

 has swollen and disintegrated ; the oosphere (o) remains in the sunken venter. 

 In many species the embryo leads a subterranean existence for several years. 

 The primary root is first formed and soon projects from the archegonium (Fig. 

 403 C, K) ; later the first leaf and the apical cell of the stem are differentiated. 

 In some species of Botrychium the embryo forms an elongated multicellular 

 suspensor at the end of which the proper embryonic mass is formed ( no ). In 

 this an agreement with the Lycopodinae is evident (cf. Fig. 428). 



