1898.] 



pRAKGKR — Fnictification of Ferns, &c. 



Ill 



The few remaining British Ferns show an arrangement 

 of the fructification quite different from any of the preced- 

 ing, and they belong to different sub-orders. In the 

 Osmundacecs, the fructification is borne in chisters at the 

 extremity of the frond. The only British representative of 

 the group is Osnumda regalis, the well-known Royal Fern, 

 whose conspicuous fructification has earned for it the title of 

 Flowering Fern. In this genus, the upper portion of the 

 fronds, which are twice pinnate, is devoted entirely to the 

 bearing of the sori. In the lower two-thirds or so of the 

 frond the pinnules are green, leafy, and finger-shaped. In 

 the upper third they are reduced to a narrow axis which 

 bears along each margin close-grouped clusters of rich brown 

 spore-cases. But in this plant again we find that there is no 

 sharply-defined line between the barren and fertile portions. 



Fig. 1. — Osmunda regalis— iirKiiw a cultivated plant). 



A little search among a number of plants will generally 



reveal instructive intermediate pinnules, among which every 



stage may be traced from the broad green barren pinnule to 



the narrow brown fertile one. This is well shown in the 



figure (fig. i) which represents a pinna taken from a large 



frond which had a fertile patch around the midrib a little 



above the middle of the frond* 



A 2 



