FOSSIL PLANTS. 423 



ble in the above mentioned figures, a close comparison with our species cannot 

 be established. It is nevertheless evident that it does not represent the Fame 

 plant as ours, as its stem, though striate, like a Catamites, is not marked like 

 ours by any knots of the articulations. Erom the mode of division, the form 

 and the size of its leaflets, this species of ours is a true Annularia, The one 

 described and figured by Messrs. Lindley and Hutton as Asterophi/llites foliosus, 

 and which does not even resemble that of Greinitz, has linear lanceolate, pointed, 

 narrower leaflets, and is not comparable to this, which I refer with doubt to 

 Annularia longifolia, Brgt., considering it rather a distinct species, under 

 the name of Annularia calamitoides, Schp. Prof. Schimper has published, in 

 his Pal. Veget., p. 349, pi. xxvi, fig. 1, a new species which, though the leaves 

 are narrower and more acute, is nearly related to this one, if not identical 

 with it. 



ANNULAKIA INFLATA, Sp. nov. 



PI. xx, fig. 1 to 3. 



THE essential difference which separates this species from 

 Annularia longi/olia, Brgt , consists in the form of the leaflets, 

 which are ob-lanceolate, obtuse, subcylindrical or inflated up- 

 wards without trace of medial nerve, or with merely an ob- 

 scure line indicating a central vessel, while the leaflets of A. 

 longifolia, are flat, with recurved borders and marked by a 

 thick, flat medial nerve. The difference in the form of the 

 leaflets is seen in fig. 3 and 4, and their comparative sections, 

 36 and 4 ft. The stem of this species does not appear as thick 

 as in A. longifolia, and the branches come out in opposite di- 

 rection from the middle of the whorls, or rather from above 

 them, than from below. 



The specimens figured are from the concretions of Mazon creek, where both 

 species are abundant, and may be distinguished always by the same characters, 

 without any form appearing intermediate. It may be that we have here two 

 parts of the same species, one representing branches growing out of or above 

 water under atmospheric influences, with dry, flat leaflets ; A. longifolia, the 

 other, representing the floating part, sustained in water by bladderly-inflated 

 leaflets, as shown in our species. But if it is so, it is peculiar that this, so dif- 

 ferent a form of a common species, has not been found elsewhere and described 

 before. 



