APPARENTLY PECULIAB SPECIES 443 
was genuine "pinnatifida, he gave it a new name taking for 
granted it was a new species. So as S. finnat. does not at 
Valparaiso vary into big pods I am more persuaded that 
yours is a representative species of W. coast of N. America. 
That neutral territory of representative species you ask 
about is just what I want to work out, but it needs great 
materials. 
Ever yours most truly, 
J. D. Hooker. 
The following comes between Darwin's letters given in 
M.L. i. 411 and 414, of which the latter is dated April 10, 1846. 
One of the great objects I had in view in my notion 
above alluded to [of the distrib. of Galapagos plants] was 
to group the plants according to their derivation, and I have 
a class in reserve for ' a'p'parently 'peculiar species, possibly the 
altered forms of introduced plants.' It is quite true that in 
most islands there is a lot of very dubious species, by no 
means to be confounded with their countrymen, and not 
polymorphous in the said island, but wofuUy near certain 
continental congeners. Thus I would divide the Galapagos 
plants into 4 groups : 1. Ubiquitous, e.g. Avicennia. 
2. Of nearest continent, as BaccJiaris. 3. Possibly altered 
state [illegible]. 4. Original creations, as Pleuropetalum 
or Scalesia. The third group may not be a large one in the 
Galapagos (according to my notions) but its acknowledged 
existence is a matter of some importance. In the cases of 
Madeira, the Canaries and Azores, said group 3 must be very 
considerable. Such however is the difference of opinion 
amongst Botanists as to what should or should not be a 
species, that the question in any shape will be a troublesome 
one, though not on that account to be dismissed unconsidered. 
I stumbled on a splendid fact the other day, that the 
Lycopodium cernuum is only found in the immediate neigh- 
bourhood of the hot springs in the Azores. When alluding 
to its distribution at p. 114 of my Flora I dared not mention 
that it was not known to be an inhabitant of Madeira or the 
Canaries, as I thought it must turn up there ; now however 
I do not expect it and feel sure that the presence of this 
torrid plant in the Azores is due to the hot springs. What 
I am most pleased at is the apparent proof of the universal 
