466 



MOSSES AND FERNS 



CHAP. 



The sexual organs of all investigated species of Lycopodium 

 are very similar, and closely resemble those of the eusporangiate 

 F'erns and Eguisetum. As in these forms the antheridium 

 mother cell divides first by a periclinal wall into an outer and 

 inner cell, the latter giving rise immediately to the sperm cells. 

 In the outer cell the divisions are much like those in Maratiia, 

 but the opercular cell does not become detached as in these, but 

 is broken through as in the Polypodiacese. In L. pJdegniaria the 

 outer wall is often in places double, as not unfrequently is the 



Fig. 244. — A, B, Very young prothallia of Lycojiodium certitiuin (L.). A, X250; B, X 200. P, 

 Primary tubercle ; C, an older prothallium of the same species with the first antheridium ( (5 ), 

 X75 ; D, a fully-developed prothallium ijir) with the young sporophyte attached, X 12 ; pc, proto- 

 corm ; R, primary root ; E, section through an antheridial branch of the prothallium of Z. phleg- 

 ■maria (L.), showing antheridia ( (J) in different stages of development ; par, a paraphysis, X 180 ; 

 F, surface view of the top of an antheridium of the same species ; 0, opercular cell, X i8q ; G, a 

 spermatozoid, X4T0; H, section of the archegonium of the same species, X 180 (all the figures 

 after Treub). 



case in the Ophioglosseae. The spermatozoids are almost 

 straight oblong bodies with two cilia, like those of the Bryo- 

 phytes (Fig. 244, G). The vesicle, which usually remains 

 attached to the spermatozoids of most Archegoniates, here is 

 almost always free, and often remains within the sperm cell after 

 the escape of the spermatozoids. 



The archegonium in its development corresponds essentially 

 with that of the other Pteridophytes. The basal cell appears 



