BRITISH FERNS. 91 



" Masses of thecae, roundish, terminal, imbedded in the margin 

 or segments of the frond. Indusium urn-shaped, of the texture 

 of the frond, and continuous with it, of one leaf, dilated upwards, 

 and opening outwards, permanent. Thecae several, sessile, 

 crowded at the base of a permanent, cylindrical, common recep- 

 tacle, whose capillary naked point projects beyond the cover, 

 each roundish, of two valves, bound by a vertical jointed ring." 

 Eng. Flora, Vol. iv. p. 324. 



Speaking of our British species, Smith describes the fructifi- 

 cation thus : " A few of the uppermost segments, terminating 

 each in a solitary, imbedded, oblong, or cylindrical, somewhat 

 urn-shaped cover, continued from the leaf, slightly winged at the 

 sides, a little dilated, not lobed at the orifice. Thecae, in a round 

 mass, attached to the base of a cylindrical slender receptacle or 

 column, which, in an early state does not project beyond the 

 cover, but afterwards acquires three or four times the length of 

 that part." Id. L c. 



This fern being, as regards Great Britain, so peculiarly Irish, 

 I have ventured to introduce the sketch of a building equally 

 characteristic of that country. 



