4 FERNS IN THEIR HOMES AND OURS. 



in rows, and are minute nut-like bodies, with the 

 elastic ring around the upper portion (PI. 5, Fig. 3). 

 With the Osimmdas, again, the spore-cases are 

 stalked ; but the ring is represented by a rudiment 

 on one side only (PI. 5, Fig. 5). With the Gleiche- 

 ttias, an order not represented by any native North- 

 American species, the ring is perfect, but passes 

 horizontally around the spore-case (PL 5, Fig. 2). 

 This order comprises many beautiful tropical ferns 

 of a climbing habit. With the Marattacece the 

 spores are in pod-like cases quite unlike those of 

 other ferns (PI. 5, Fig. 6) : in fact, the difference is 

 so great, that Sachs, in his " Text-Book of Botany, 

 contemplates their removal to a separate class b) 

 themselves, although most of their characters 

 agree with the regular type. The Botrychiums 

 (PL 19) (Ophioglossacetz) differ so much from ferns 

 in general, and it is so clear, as shown by Sachs, 

 that they belong to another class of plants, that we 

 will for the present pass them by, and consider 

 them at a later moment among the Fern Allies. 



Among ferns of the various orders, the mode of 

 development from the spore is not always exactly 

 the same. There is not sufficient difference be- 

 tween them, however, to prevent us from consider- 

 ing Pteris serrulata, the one we have chosen as an 

 example, to serve as an illustration of all. The 

 spores of ferns should usually be sown soon after 

 they are ripe. Some, however, are said to retain 



