VIII 



THE P TERIDOPH \ 'TA~OPHIOGLOSSA CEA£ 



The prothallium of BotrycJiiinn lunaria ^ is much smaller and 

 does not grow to the surface of the ground. It is oval in form, 

 and consists of a mass of firm tissue, brownish towards the 

 outside and colourless within, where the cells are also larger. 

 Scattered root-hairs grow from the superficial cells, and the 

 prothallia are monoecious. The antheridia, which correspond 



c 



D 



Fig. io8. — Ophioglossiitn pedunculosuin (Desv.). A, B, Prothallia, X 2 ; T, the primary tubercle; 

 C, antheridium, X200 ; D archegonium ; E, a young embryo (after Mettenius). 



closely to those of Ophioglossuin, are produced principally upon 

 the upper surface, the archegonia below. The latter correspond 

 in structure to those of Ophioglossuni, but to judge from 

 Hofmeister's figure the neck is somewhat longer and projects 



■^ Hofmeister, I.e. 



