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 
Fic. 68.—Prothallus of a southern fern (Pteris serrulata). 
a, actual size ; 4, 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. 
