POLYPODIUM DRYOPTERIS. 17 
eyes become a little blind to the direct object of 
the walk. What wonder, then, if you return, as I 
did, fernless, but with an appetite as keen as a 
hunter's from the pure air sweeping to you over 
the white-capped waters of the Frith of Forth ! 
My first personal acquaintance with Dryopteris 
(I must be allowed to use their Christian names !), 
in its wild state, was made between Hawthornden 
and Koslin, in a lovely walk raised a little above 
the flowing rippling Esk. In the woods, on either 
side, it grows in great luxuriance, and many a root 
found its way into the black bag. It gave rise to 
a great argument : one of the party declared it to 
be Calcareum. In vain I said Calcareum had not 
as yet been found in Scotland ; in vain I pointed 
out the true characters .of Dryopteris, the pale 
green of the young fronds with their three little 
rolled-up balls, the flat compact forms of the 
larger fronds, descanting meanwhile on the blue 
green of Calcareum with its larger more straggling 
fronds, its narrower pinnaB, its sharper serrated 
pinnules. It would not do, and, doubtless, to 
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