226 Tue Microscope. 5 
grow about the conical base, and I carried one of those excrescences 
a thousand miles to show it to my friends, only to find that a dozen 
cypress trees, knees and all, were flourishing within half a mile of 
my own front door. Some of these I had passed almost every day 
for a dozen years, yet had never seen them. But who could see through 
a hemlock hedge? It was Thoreau, I think, who intimated that he 
did not need to travel in search of rareties, for he expected to find 
even the Victoria regia in Walden pond. ; 
The study of the trees is a science worthy of a place by itself; it 
might justly be separated from that of the smaller and humbler 
pheenogams and flowerless plants, aud the amateur who should de- 
vote himself to the pursuit would find it an entrancing one, whose 
attractions neither the cold of winter nor the heat of summer could 
diminish. And when he could do no more than name the tree from 
the aspect of its naked branches, or from a glance at its leaves, he 
would be a botanist indeed. 
If there are few who know our trees in the winter, are there 
many more who can recognize them by their foliage in the summer? 
The flowers or the fruit may divulge the secret, but the leaves 
aloneadd for most of us who are fond of botanical study, an element 
that more frequently than not gives us trouble. And again it 
sometimes happensthat the leaves of two trees generically distinct, 
or even members of distinct orders, may be so nearly alike 
in form, size, texture and general appearance, that we can only say 
that one leaf is from one of two trees, and that the other may also 
be from one of two trees, but further and with more definite state- 
ments we dare not venture. 
Then the microscope may came into use, although it may be 
nothing more than a pocket-lens, for Nature is not so limited in her 
resources that she is compelled to make the leaves of distinct genera 
exactly alike, however they may appear to the nakedeye. This fact 
and the usefulness of the pocket-lens in the discrimination, have 
recently become prominent in my own experience in connection with 
an effort to identify the leaves of Catalpa bignonioides, Walt., and 
those of Paulownia imperialis, Lieb., when removed from the trees. 
These trees belong to distinct natural orders, Catalpa to the 
Bignoniacez, Paulownia to the Scrophulariacee, yet I do not believe 
that any amateur botanist, and I feel considerable doubt as to the 
ability of the professional, positively to distinguish the leaves of the 
one from those of the other, unless he knows the microscopical 
secret, even when the two trees are standing side by side, provided 
that each is deststute of flowers and fruit. Both trees, at least in the 
