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.
NEW FORMS OF FERNS.
By Charles T. Druery, F.L.S.