452 
PALAEONTOLOGY OF ILLINOIS. 
are, however, distinguishable at the bottom of some cicatrices. 
Their size is proportionally small. The species is perhaps re¬ 
ferable to some of the numerous varieties ascribed by authors 
to Stigmaria ficoides . 
Prof. Goppert ( Flora dcs Ubergangsgebiryes, p. 246, pi. xxxii, fig. 3,) lias 
published as S. ficoides var. el/iptica, a specimen apparently decorticated, with 
oblong, elliptical and unequal cicatrices. These, by their irregularity of form, 
size and position, evidently belong to a species different from ours. The same 
author, in his Gattungen Liv .1, 2, pi. xv, fig. 49, shows part of the stem of a 
Stigm aria ficoides, whose cicatrices, taken from within the cylinder, are ellipti¬ 
cal, while those of the surface are round. But in the specimen here figured 
we have the true cicatrices of the cortex. I do not think it advisable to enu¬ 
merate and describe the different forms of Stigmaria as mere varieties of the 
same species. The vegetable remains described in the next genus, demonstrate 
that even the roots of plants of the Carboniferous age are distinguishable by 
peculiar forms and peculiar cicatrices. It is my belief, the genus Stigmaria 
does not represent t ree roots, but floating stems, of which species of the genus 
Sigillaria constitute the flowers or fruit-bearing stems ; the difference in the 
form, the size, and the relative position of the scars ought to be admitted as 
specific characters in the same manner as for the species of the genus Sigillaria. 
Duquoin ; shales over the main coal. 
Stigmaria umbonata, Lesqx. 
Gcol. Kept, of Penn., p. 870. 
I refer to this species remains of a Stigmaria found in abundance in the 
shales of the coal at Colchester, where the leaves are seen in connection with 
the stems. The cicatrices of the stems are of much larger size than those of 
Stigmaria ficoides , and the flattened leaves arc twice as broad, measuring half 
an inch or more in diameter. 
Genus STIGM ARIOIDES, Lesqx. 
The species referable to this genus, very variable in form, 
tuberculose, or globular, or cylindrical, are apparently tree 
roots or rhizomas. They have, as common characters, round, 
