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 same 
plant as ours, as its stem, though striate, like a Catamites, is not marked like 
ours by any knots of the articulations. From 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. Findley and Hutton as Asterophyttites foliosus, 
and which does not even resemble that of Geinitz, 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, Sehp. , Prof. Schimper has published, in 
his Pal. Yeget., 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. 
Annularia inflata, Sp. nov. 
PI. xx, fig. 1 to S. 
The essential difference which separates this species from 
Annularia longifolia, Brgt, consists in the form of the leaflets, 
which are ob-lanceolate, obtuse, subcylindrical or inflated up¬ 
wards without trace of medial jjprve, 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 b. 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 j 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. 
