THE LATE SUMMER FLOWERS. 249 
The ferns have now mostly passed their prime, but 
there are two which have still a special interest. It was 
a surprise and a pleasure to me to find the bladder fern, 
( Crystopteris fragilis, Bernh.), in the woods along Lake 
Quinsigamond, after having looked long and patiently 
for it elsewhere. To me it is one of the most graceful 
and delicate of our native ferns, rivaled only by a few, 
among which I must admit the climbing fern (Lygodium 
palmatum, Swartz). This is perhaps the rarest of our 
local ferns, certainly in this part of our county. It is 
the only one of them with the power of climbing; and 
when growing in profusion it covers the neighboring 
shrubbery with a tangle of the most delicate greenery. 
I have in mind now a meadow a dozen miles away, with 
a broad clear brook running through it, and a wilder- 
ness of shrubbery enclosing it, where, on an early Octo- 
ber day some years ago, I gathered it for the first time. 
My own experience enables me to appreciate the enthu- 
siasm of the fern-collectors who have ransacked all parts 
of the earth for these beautiful forms. 
When I thought I had found all the species of 
Bidens that probably occur in this locality, one more 
species (B. Beckit, Torr.), the water marigold, presented 
itself to me at the upper end of Lake Quinsigamond, 
near where the water crowfoot had previously been 
found. This gives us five of the six species of Bidens 
32 
