|SECOND GEOLOGICAL SURVEY OF PENNSYLVANIA - REPORT OF PROGRESS
P. DESCRIPTION OF THE COAL FLORA OF PENNSYLVANIA
AND OF THE
CARBONIFEROUS FORMATION THROUGHOUT THE UNITED STATES
BY LEO LESQUEREUX; ©1879
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©George Langford III, 2011
|These plants, generally of a soft cellular tissue, are soon decomposed
under atmospheric action. Though extremely numerous at the present
time, very few have been found fossil. It is merely from the recent
formations, the tertiary especially, that some species have been
described. They are mostly referable to Hypoxileae, a class of minute
plants, intermediate between the Fungi and the Lychenes which appear
like dots or small black spots, attached to decaying leaves or stems.
The characters of these vegetables are derived, in their original
state, from minute spores or seeds, inclosed in capsules of diverse
forms. They can be studied only with a microscope of a high power, and.
therefore cannot be positively determined from fossil specimens. Two
species of this kind only have been described from the coal measures of
Europe: Excipula Neesii, Goepp., and Diplazites Rhabenhorstii, Gein., both
discovered upon the epidermis of pinnules of ferns.
In the North American Coal measures, remains of stems and leaves of large size, like those of the Cordaites, are often dotted with small, convex, round or oval protuberences, which, breaking through the tissue and deranging its regular conformation, seem to represent small Fungi like species of Spheria. It is however extremely hazardous to consider them as organized bodies. For in many cases, these pustular projections are evidently produced by mere physical cause or mechanical agency. In the semi-anthracite coal of Trevorton, for instance, not only the vegetable remains, but the shale, even the coal, are covered and filled with round vesicles, perfectly similar in shape and size to species of Hypoxileae. Some fossil stems and leaves, therefore, seem really to have been inhabited, when living, by groups of Spheriae. But as the same kind of productions are seen upon inorganic matter as well as upon remains of plants, they are evidently the result of a casual interruption in the process of evolution and dispersion of gazeous substances, like the vesicles produced by the action of caloric upon a matter in a state of semi-liquefaction.
In the Geol. of Penna., 1858, p. 847, I have referred to Polyporites Bowmanni, Ll. & Hutt., a form which closely resembles the hard mushrooms, Bolets or Polypores, seen in the woods now, attached to the branches of trees, and characterized by concentric zones of alternate layers of different color. The English specimen on which the fossil species was established has been recognized as a scale of fish. The American one is much larger; the zones less regular; and as no animal remains have been found in the Anthracite measures in connection with it, it cannot be supposed to represent a fish scale. I have seen, of late, in beds of hard ferruginous clay of the Colorado Tertiary, fragments marked with alternate red and yellow bands; regularly placed around a basilar or eccentrical point, presenting an appearance like that of the specimen of the Carboniferous, and seemingly explaining its nature.
The organism described here below is of a far different character, and is to my persuasion the representative of a true Fungus.
Fungous filaments of hard substance, disposed in branches abnormally divided and often anastomosing; generally living under the decaying bark of trees.
Until now, these plants have been very rarely found with organs of fructification, and therefore are considered as a kind of Mycelium, adventive filaments which represent the first stage of life of the mushrooms.
Stem or principal axis flattened, irregularly round or polygonal in outline, divided all around in branches, either simple or forking, even anastomosing in various directions, inflated upwards, club shaped and obtuse, slightly flattened by compression; surface marked by a netting of narrow wrinkles resembling veins, with intermediate thin veinlets.
The figure exactly represents the specimen. The central or primary axis is quite flat, the branches half round, inflated to the obtuse apex, one to three millimeters broad in the lower part, divided at the base or joined by abnormal anatomosing divisions, often connected in the upper part by thin filaments in right angle, scarcely perceivable without glass. The surface of the flattened axis is smooth, that of the branches wrinkled.
This form, examined by competent mycologists, has been recognized as very closely allied to Rhizomorpha subcorticalis, and other species of the present time. Its relation to Fungineae has not been contradicted. Indeed, it cannot be compared to anything else than to a Rhizomorpha, except, perhaps, to the borings of some insects into the wood or under the bark. The furrowed passages of insects, however, have by their regularity, especially in the equal dimensions of their tunnels, a far different character. In this specimen the axis is flattened, while the branches are gradually thicker toward the apex, and the filaments derived from the branches are seen penetrating around or on both sides, like very slender threads, scarcely perceivable to the eye. No work of insects can produce such divisions.
For authorities supporting the reference of this vegetable to a Rhizomorpha, I mention the names of Dr. Casimir Roumeguere, of Toulouse, France, and of Prof. Chas. H. Peck, of Albany, both celebrated micologists, to whom I owe the communication of numerous specimens for comparison. Prof. Sam'l H. Scudder, of Cambridge, examined the specimen in regard to its possible relation to borings of insects, of which he has made a peculiar study. He considers the characters of the organism as without relation to any kind of animal process. His opinion on this subject is unquestionable.
Habitat—Shale of the Cannelton coal, under the bark of a Sigillaria. The habitat of this organism is an almost positive proof of its relation to Rhizomorpha, plants which at the present epoch live under exactly the same circumstances.