The Sporing of the Fern 



251 



The adders'-tongues, next of kin to the ferns 

 and the horsetails, or scouring-rushes, both shed 

 spores, which develop into prothalli. So do the 



FlG. 68. Prothallus of a southern fern (Pteris serrulata). 

 a, actual size ; 6, much magnified. 



lycopodiums, which, under the names of " ground- 

 pine," "club-moss," or " trailing-evergreen," are 

 familiar to almost every one who has summered in 

 New England. 



