108 Ohio Naturalist. [Vol. 1, No. 7 



in Fig. ] 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 each 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 this 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 i^revailingly 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 elougatiori 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 



