268 HISTORY OF BRITISH FERNS. 



The fructification is a blunt oblong cone, more than aii 

 inch long, terminating the main stem, and supported on a 

 stalk about equal to its own length above the uppermost 

 sheath. The whorls of scales in the mature cone are quite 

 separated, and expose the white spore-cases attached to 

 the margin. The scales in this species exceed a hundred 

 in number. The fructification is mature about June. 



Besides the more usual form just described, there are 

 some curious variations to which this plant is liable. 

 One of the most remarkable has been called polystaohyon. 

 Its peculiarity consists in its having more or less of 

 the branches of the two upper whorls terminating in cones 

 of fructification ; the usual habit of the plant being to pro- 

 duce only one cone, and that on the central stem. The 

 cones produced by the branches are, we believe, always 

 much smaller than the ordinary cone of fructification pro- 

 duced by the main stem, and they are darker-coloured and 

 more compact. It has been suggested, that the produc- 

 tion of these lateral fructifications is accidental, owino- to 

 the destruction of the top of the main stem, but this 

 explanation is quite insufficient, since they are sometimes 

 produced along with the central head, which, moreover, 

 varies when accompanied by them, being sometimes of the 



