496 
PALAEONTOLOGY OF ILLINOIS. 
of our time, which bear their fructifications either as separate racemes or on 
peculiar divisions of their fronds. The fructifications of species of the genus 
Odontopteris , so closely related to Neuropteris , are known for Odontopteris 
Schlotheimii and 0 . Reicliiana, Gutb. The fertile pinnae, not yet found in con¬ 
nection with sterile fronds, bear inflated, round leaflets resembling small blad¬ 
ders, which have no relation whatever to the intumescence of veins considered 
as the fructification of Neuropteris. 
Still more than their fructification, the rhizomas of ferns have hitherto been 
unknown to palaeontologists, at least from the Coal Measures. Prof. Goppert 
has given, in his Foss. Farnkreuter, p. 91, tab. 33, fig. 1, the only fragment 
which as yet has been published by European authors, as evidently belonging 
to true rhizomas of the coal. In his Pal. Veg., Prof. Schimper has published, 
under the name of Rhizomopteris, two fragments of plants, Selaginites Erdmanni ) 
Gein., and Selaginites uncinnatus , Lesqx., which, from the spiral development of 
their branches, their ramifications and their scales, he considers as representing 
small rhizoma of ferns rather than Lycopodiacece. I cannot agree, on this sub¬ 
ject, with my celebrated friend. The plant published ns Selaginites uncinnatus, 
Lesqx., vol. ii, p. 446, pi. 41, of this Report, is too slender, and has too slender 
divisions to represent a rhizoma, even of a climbing fern. Its slender branches, 
rather pinnately placed, are not more curved in spiral than they may be in 
some of our species of Lycopodium , and the divisions are evidently pinnate, 
like leaflets, and not scattered like hairs. The plant named Lycopodites Erd- 
manni, by Geinitz, and which, as Prof. Schimper remarks, is different from 
L. Erdmanni of Germ., has, like our Selaginites crassus, the ramification and 
appearance of a Lycopodium, but from the examination of peculiar specimens 
of the same species, seen by the author, it seems to belong to a rhizoma. Even 
admitting that these two species represent climbing or aerial rhizomas, this 
small proportion of organs of this kind, compared with the numerous species 
of ferns known from the Coal Measures of Europe, would be unexplainable, but 
for our American species. For the concretions of Mazon creek, and only 
these from the whole extent of our Coal Measures, have furnished us numer¬ 
ous specimens of eight species of these organs, some of them referable to sub¬ 
terraneous rhizomas. It is, therefore, apparent that the organs of the ferns of 
the Carboniferous epoch were the same, and in the same proportion, as those of 
our time, but, that some of these, like rhizomas and fruit-bearing fronds, have 
been more generally destroyed in the shale on account of their soft texture. 
The inflated subcylindrical base of a species of Annularia and of a hepido- 
dendron are also two remarkable characters, not recognized as yet in the same 
kind of plants of the Coal Measures, and which we owe still to the peculiar 
preservation of vegetable remains in the concretions of Illinois. Species of 
the genus Annularia may have been represented in the swamps of the Carbon¬ 
iferous period by two kinds of leaves, according to their growth, either in water 
yf 
