Lesquereux. | 174 [Oct. 19, 
in concentric zones by penetration of iron in such a way that they 
exactly represent the appearance of the fossils described by the English 
authors. The zones, about two millimeters wide, are of different hardness, 
and the soft white ones being more easily disintegrated, they form a series 
of alternately elevated and depressed concentric bands, similar to those 
described as characters of the Polyporites of the coal. 
However this may be, we have now from the Carboniferous a fossil plant 
which is by all its characters positively referable to the Fungi. This plant 
which was discovered under the bark of a Sigillaria is referable to the 
Genus Rhizomorpha, a fungose substance which even until the present 
time has very rarely been recognized with organs of fructification, and is 
therefore admitted as a kind of mycelium or as the first stage of the life of 
a fungus. Species of variousand numerous forms of these vegetable organs 
are commonly found under the bark of trees or between layers of decaying 
wood in the forests, and some have been described under different specific 
names. 
RHIZOMORPHA SIGILLARIA, sp. nov. 
Pl. £ fig. 9. 
Stem flattened irregular in form, round, polygonal, elongated and linear 
or amorphous ; branches diverging all around, either simple or forking, 
even anastomosing in various directions, inflated towards the top, club 
shaped and obtuse or slightly flattened by compression, and marked upon 
the surface by a netting of narrow wrinkles resembling veins and their 
divisions in veinlets. 
The figure exactly represents the specimen which botanists will easily 
recognize as bearing the appearance of some of our present so-called species 
of Rhizomorpha. The surface wrinkles, distinctly seen in fig. 9 b enlarged, 
seem to have been produced by compression and contact of an upper layer 
of bark reposing upon them. In their normal state the same appearance 
is remarked upon living forms of these Fungi. It is the same with the 
flattened body, the mode of branching, the different size and length of the 
branches, which are evidently widened and modified in their form and di- 
rections according to the space left under the bark for their development. 
Though no doubt could be entertained about the relation of this or- 
ganism, which was discovered in detaching the upper layer of bark of a 
Sigillaria, 1 nevertheless referred the matter to the opinion of some of my 
corresponding friends, to whom I[ sent the figure of the plant in order to 
have every possible evidence cn this subject. Among others Dr. Casimir 
Roumeguére of Toulouse, France, who has large collections of Fungi 
and who is known by numerous scientific memoirs on this difficult branch 
of botany, answered my request by the communication of many specimens 
of the different forms of Rhizomorpha of our time whose characters are 
comparable to those of the fossil one. Remarking on its relation as far as 
it could be recognized from the figure of this organism (the same as that. 
reproduced here) he says: I was extremely interested by the examination 
of your Rhizomorpha Sigillarve and startled by the appearance of structure 
which seems to relate that American fossil organism to European con- 
