712 Aspidium spinulosum and its Varieties. [ November, 
intermediate forms connecting the second center with the first, 
then the probabilities are in favor of the second plant being a dis- 
tinct species; but if the second is directly connected with or 
related to the first by a graduating series of forms and other 
characters, then we are justified in regarding the second as a 
variety of the first, the intermediate forms being rather proofs of 
the fact than otherwise. 
This is exactly the position in which I find Aspidium spinulo- 
sum and its var. intermedium. 
As for the so-called var. di/atatum, as we have it in Eastern 
Massachusetts, I have not been able to discover any really good 
distinctive characters to justify regarding it as anything more than 
a highly developed state of sfzzulosum. Not only does the form 
of the fronds often agree with Swartz’s description of the species, 
but frequently, even in very large specimens that appear at: first 
sight more compound, they are only bipinnate in structure. I 
have so many times traced the ordinary form of the species step 
by step into our dilatatum that I have no faith in it as a variety, 
but think it should be embraced in the specific description. The 
smooth under surface and naked indusia clearly place it with the 
specific form, and in the specimens examined I have found the 
situation of the sori on the veins exactly the same as in the 
species. 
On the other hand the more northern form, peculiar to the 
mountainous regions of New Hampshire and Vermont, is so dif- 
ferent in appearance, being in every way larger and more com- 
pound, that it may be desirable to have some way of designating 
it, even though the characters are of secondary importance. For 
this reason it may be as well to retain the variety subject to this 
limitation. 
Var. Boottii, I have always been inclined to regard as a distinct 
species on the supposition of its being a probable hybrid between 
A. spinulosum (intermedium) and A. cristatum, but if it is to be 
considered only as a variety, then it comes nearer to cristatum 
than it does to spinulosum. So far as my own and the observa- 
tions of my friends extend, whenever it varies at all it recedes to- 
__ ward cristatum. Thus apparently indicating its origin. I have 
not Pease < with a . botanist who did not express some such feel- 
ani Portion of ie Eie frond certainly x resembles the e a 
