98 HISTORY OF BRITISH FERNS. 



This is a very peculiar plant, exceedingly interesting to 

 the student of Perns,, from the differences of structure and 

 development it exhibits as compared with the majority of 

 Ferns. It is an almost stemless plant, furnished with a few 

 coarse brittle fibres, and a bud springing from the perma- 

 nent point which represents the stem. Within this bud, 

 before the season at which the fronds are developed, they 

 may be found in an embryo condition, perfectly formed, the 

 two branches of the frond placed face to face, the fertile 

 being clasped by the barren one. This new frond springs 

 up annually, and perishes before winter, and in the majority 

 of cases is not very conspicuous. The size varies from 

 three to eight or ten inches in height, the lower half con- 

 sisting of a smooth, erect, cylindrical, hollow stipes, the 

 base of which is invested by a brown membranous sheath, 

 which had covered it while in the bud. 



Above, the frond is separated into two branches, one of 

 which is spreading, pinnate, leafy, lance-shaped ; the pinnae 

 crescent-shaped, or somewhat fan-shaped approaching to 

 lunate, filled with a radiating series of two or three times 

 forked veins, such as occur in Adiantum, one vein extending 

 into each of the crenatures into which the margin is divided. 

 The other branch is erect, fertile, compoundly branched, 



