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 Stigmariaficoides. 



Prof. Goppert (Flora dcs Ulergangsgelirycs, p. 246, pi. xxxii, fig. 3,) has 

 published as S.Jicoidesvar. elliptica, 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 Gattunyen Liv .1, 2, pi. xv, fig. 49, shows part of the stem of a 

 Stigmdriu 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 ihe different forms of Stiymaria 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 tree roots, but floating stems, of which species of the genus 

 Siy'dlaria 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. 



STI&MARIA UMBONATA, Lesqx. 



Gcol. Kept, of Penu., 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 

 Sligmaria Jicoides, and the flattened leaves are twice as broad, measuring half 

 an inch or more in diameter. 



GENUS STIGMARI01DES, Lesq 



x. 



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, 



