268 
HISTORY OF BRITISH FERNS. 
The fructification is a blunt oblong cone, more than an 
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 polystachyon. 
Its peculiarity consists in its having more or less of 
the branches of the two upper w^horls 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, owing 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 
