108 
Ohio Naturalist. 
[ Vol. 1, No. 7 
in Fig. 1 C presents one simple and one compound leaf. At D greater 
complexity is indicated, there being in many plants besides the 
central flower three instead of only two axillary ones, and only one 
of the subtending leaves is compound. In the case shown at E two 
of the three involucral leaves are compound. As shown in F and G 
four leaves may contribute to form the involucre and eacli one 
subtend a flower; in some cases two of the leaves are compound, in 
others three or even all may be compound. Still other variations 
along tli is line occur, but space forbids a fuller enumeration. 
It should be stated that although the pedicels and leaves as 
shown in the diagrams (Fig. 1) occupy but a small portion of the 
circle, as a matter of fact the leaflets are spread and so disposed as to 
occupy the entire area when viewed from above the plant, the leaflets 
being equidistant from each other, or contiguous but not overlapping, 
and therefore taking the most advantageous position so far as 
sunlight is concerned. 
The very striking variation in regard to presence or absence of 
the petiole to the involucral leaves has been previously noted. An 
inspection of a very large number of specimens collected in the 
vicinity of Columbus and in Perry and Logan counties, as well as of 
specimens kindly sent for the purpose by Mr. F. H. Burglehaus, 
Prof. A. Wetzstein, and Supt. H. N. Mertz, shows that petiolate 
forms occur exclusively in some localities (Northwestern Ohio); in 
other places the sessile form only obtains (Eastern Ohio); and yet 
elsewhere both forms are about equally represented (Central Ohio). 
We can not regard the petiolate forms as in any real sense a variety 
(much less a distinct species)— since both sessile and petiolate leaves 
occur in countless cases on the same plant. But where the petiolate 
form occurs prevailingly or may be exclusively, it would be advan- 
tageous to designate the same; therefore I propose as follows: 
Syndesmon thalictroides f. PETIOLATA nova forma. Involucral 
leaves prevailingly or exclusively with petioles 2-10 or even 25 or 
more millimeters in length; otherwise like the typical species. 
Toledo (F. H. Burglehaus), St. Marys (A. Wetzstein) and West 
Mansfield, occasionally at Columbus and Rendville. 
Comparatively few monstrosities were observed. In one case 
only did merely one leaf and two flowers occur; often but one 
flower develops though two leaves occur as usual ; in a few cases a 
single small leaf was seen on a pedicel. A more common teratolog- 
ical variation was the elongation of the axis at the usual point of 
insertion of the flowers and involucral leaves, often distantly separ- 
ating the leaves with their axillary flowers; in one case the distance 
between the points of insertion of the leaves was nearly two inches. 
The sepals are occasionally excessively numerous. 
A characteristic very prominent is the similarity of the several 
stems that come from the same root. If one presents the typical 
