68 BRITISH FERNS. 
its cultivation in pots and under glass must be 
resorted to. 
9. SMITH’S FERN. Roserranvm. 
Polypodium roberiianum, Hoffman. B. F. 63. 
Polypodium calcareum, Sir J. E. Smith. 
The caudex is dark brown and creeping ; the fronds 
make their appearance in May, and both in their 
habit and their mode of unfolding differ from those of 
the Oak Fern: they never exhibit that appearance 
of three little balls on wires which I have mentioned 
4s such an excellent characteristic of the Oak Fern; 
but all the pinnules before unfolding appear somewhat 
globular, and the first pair of pinne differ from the 
Second scarcely at all except in size. The stalk is 
much thicker and more succulent than in the Oak 
Fern, and rather more sealy ; both the stalk and leafy 
portion of the frond are of a dull green, having no 
similarity whatever to the exquisite colour of the Oak 
Fern. The frond attains its full development in July, 
and matures its seed in August: its form when fully 
“expanded is triangular, the base being shorter than the 
sides and altogether not unlike that of the Common 
_ Brakes: the pinne are opposite; the first pair have 
always a short naked footstalk ; the d pair have 
frequently, but not invariably, a similar footstalk ; and 
