By Willard N. Clute.

Living as I do in the midst of a region rich in specimens of the ternate Botrychiums, I have taken more than ordinary interest in the discussion of the relative rank to which the various forms should be assigned. After considerable study of the subject which has consisted of a careful balancing of the degree of differentiation in each form, as well as an examination of much material both in the herbarium and in the field, I have come to certain conclusions which I purpose to set down here.

Before the separate forms are discussed it may be well to say a few words on the variations of Botrychium ternatum in general. It is a noticeable fact that all the so-called new species of this section of the genus, have been based primarily upon the cutting of the sterile part of the frond. This is all the more remarkable since there are probably no other genera in which species are founded on the minor outlines of a mere leaf. One has but to turn to nature in any clime to see that leaves are not invariably of the same shape. Note the wide variation in the moonseed, the hollyhock, the sassafras, and some of the buttercups among flowering plants, and if it be contended that the cases are not parallel, take as further illustration the blood-root, which, like the Botrychium, produces but one leaf a year, and note the cutting of its single leaf. If all these forms of Botrychium are species, why have not the forms of the bloodroot been segregated? Moreover, if we are to recognize these forms of Botrychium as species, why should we not also recognize as such the three hundred forms of Athyrium filix-foemina, or the hundred or more forms of Scolopendrium? It is unavailing to say that these latter are mere gardeners’ varieties, for we have it on the authority of Mr. Druery, who is familiar with them all, that a large number come true from spores.

Experiments with flowering plants have shown that the thickness of leaves and the amount of cutting of their edges, may be altered by different degrees of moisture, sunshine, etc., to which they are exposed, and we may infer as much for the ferns. This being so, it is not difficult to account for the slight variations in cutting exhibited in plants from widely separated points in the United States.

It is, of course, possible to follow the latest writer on the subject, and consider each extreme of variation a distinct species, but I do not agree with him in the opinion that the naming of varieties is a stupid practice, nor do I see that it necessarily follows that because a species was named Japonicum from Japanese specimens that we must infer that its centre of distribution is in Japan. As I understand it, to take a familiar example, B. ternatum stands for a plant possessing certain characters no matter where found. If we should find another Botrychium that differed from this in some specific way, it would be correct to call it another species; but if it showed minor differences, slightly thicker or thinner leaves, a longer or shorter stipe, a little deeper notching of the leaves, etc.—all characters that vary with the locality—then it would seem more properly referred as a variety of the first species.

As I have noted in this journal there are certain slight differences between the Japanese B. ternatum and our familiar species of Eastern America, but these are not enough, I now believe, to make them two separate species, since all the differences are found in the texture and cutting of the sterile part of the frond. Under such circumstances I would arrange our American forms as follows:

Botrychium ternatum obliquum (B. obliquum Muhl.). The common form in the North Atlantic States.

B. t. obliquum forma DISSECTUM (B. dissectum Spreng.). An exact duplicate of the preceding form in everything except the cutting of the pinnules. These latter characterized by a paucity of tissue between the terminal veins. Has the same habitat and range, and the same peculiarity of waiting until July or later before putting up its leaf for the season. No more entitled to specific rank than the “cut leaved” birch or elder.

B. t. obliquum forma INTERMEDIUM (B. obliquum intermedium Unde.). I would call this a mere form, comparable to any of the chance varieties of Athyrium filix-foemina.

B. t. obliquum forma COULTERI (B. Coulteri Unde.). A western form rather more fleshy than that of the East. Grows in geyser formations which may account for the difference in its appearance.

B. t. obliquum forma OCCIDENTALE (B. occidentale Unde.). Closely related to the preceding, and, in my opinion, a phase of it. Both good representatives of the western form.

B. ternatum Oneidense (B. ternatum var. Oneidense Gilbert). This, the most strongly marked of the forms in the Atlantic States failed to receive a place in the recently published index to the described species of Botrychium. It can be distinguished at a glance in field or herbarium by its broad and slightly divided pinnules, and is very common in central New York. The fronds, notwithstanding their broad pinnules, are among the smallest of the group. If any of our forms of Botrychium are entitled to sub-specific rank, this is certainly the one.

B. ternatum silaifolium (B. silaifolium Presl.). This is also mainly a western form. To it, however, I would refer the plant recently described by Mr. Gilbert as B. obliquum Habereri from central New York. I have examined the type specimen and in my opinion it agrees perfectly with specimens of silaifolium from California identified by Dr. Underwood. Even the striations produced in the pinnae by drying appear identical. I should call this a sub-species, as it does not approach the type as closely as the others.

So little is known about B. biternatum Unde. and B. tenuifolium Unde. that I shall not attempt to place them. Judging from what I have seen of the latter, and I have seen numerous plants in the field, I should consider it a form of obliquum and I suspect that biternatum will prove to be based upon aberrant plants of this which have fruited in spring instead of autumn. In regard to this, Mr. W. W. Ashe has recently informed me that many spring-flowering southern plants do not flower in the North until late summer. It is possible our ferns may have similar changes in their fruiting season.