| 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 |
Tables of Contents:
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All Four Volumes: Scans and Webpage ©George Langford III, 2011 |
Trunks of Ferns are represented in the coal measures in two different
ways, either by silicified whole fragments, generally transverse
sections of trunks, or merely by pieces of the bark, preserved in the
shale and characterized by the configuration of impressions, marking
the points of attachment of the petioles. As Tree-ferns are now
cultivated in the conservatories, they are generally known. The
similarity of the figures which represent these points of attachment in
a fossil state will be easily recognized by those who have seen
Tree-ferns of our time. These scars are generally oval in outline,
placed in spiral, though sometimes contiguous or joined at their ends,
thus seemingly in longitudinal series. According to their characters,
which are peculiar, varied indeed, and apparently specific, the plants
which they represent may be considered in the four following generic
divisions*:
Tree-ferns are common enough in the coal flora of this continent, while in Europe they are rarely found, and, according to Grand'Eury, mostly limited to the strata of the upper coal measures. Goeppert has some species from the Permian under the generic name of Protopteris and Caulopteris. We have them already in the Devonian as seen from the species described by Dawson and Newberry. None as yet are known from the sub-conglomerate coal, and none either from above the Pittsburgh coal. They are locally very abundant. In the shale of the coal they bear in their distribution the same proportion as trunks of living trees may bear to the amount of remains deposited for successive years by their branches and foliage. Trunks of Psaronius are found mostly in South Ohio, on Shade river, and in Kentucky, along the Great Kanawha river. They are derived all from the same horizon, a heavy Sandstone underlying the Pittsburgh coal. | |||||
| Stemmatopteris, Corda. Trunks erect, cylindrical; scars
large, disciform, oval round or ovate, not contiguous, disposed in
quincunxial or spiral order; outside borders or rings flat; internal
disk formed by impressions of fascicles of vascular tissues, shaped
like a horse-shoe, the horns curving inward in the upper part of the
scars, either short and hooked, or descending below the middle of the
scars and there united.— Atl., Plate LIX.
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Scars of medium size, exactly
oval; borders large; disks scarcely broader in the Middle, slightly
curving up to the horns, which are short, at a distance from each
other; borders fringed by short scales or hairs; epidermis of the bark
grained like shagreen. The scar are seven centimeters long and four broad, the flat borders about one centimeter ; the surface of the disks is marked by prominent smooth vascular dots, irregular in size and distance. A specimen from Oliphant bears scars ten to fifteen centimeters in vertical distance, five to six in horizontal, with scales somewhat.larger at the base. Another from Cannelton has the bark grained like shagreen. Habitat—Concretions of Mazon Creek, finely preserved, Mr. S. S. Strong. Shale of coal No. 1 of Oliphant, Pa. cabinet of Mr. R. D. Lacoe; Cannelton coal, Mr. I. F. Mansfield. | |||||
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Scars larger than in the former species, oval, rounded on the lower end, marginate at the other; borders broad and surface smooth; disks divided into two opposite semi-lunar lobes by the vascular impressions. The scar is nearly eight centimeters long, four centimeters broad; the disk is divided into two separate lobes, each irregularly oval, the outside line parallel to the borders, the inside close at both ends, more distant in the middle or semi-lunar in opposite directions. The vascular impression is somewhat like that of Atl., Plate LIX, f. 4, with this difference, that the medial lines descend to the base and join it by an outside curve, dividing the disks in two halves. It is not possible to see which end of the scars is the upper. This scar may be that of a Megaphytum. Habitat—Cannelton, Pa.; Mr. I. F. Mansfield. | |||||
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Stem long and small, covered
with a coating of rootlets; leaf scars distant, long, narrowly oval,
obtuse at both ends, distinct, even under the thick coaly layer,
distant and alternate; vascular impressions horse shoe shaped; horns
short, nearly contiguous in their curve. The stem measures at least one meter in length, and its width does not average more than eight to nine centimeters in the whole length. The scars are alternate, very distant, twenty centimeters from the base of one to the top of the lower one in the series, but transversely close, three to four centimeters, also between the corresponding or opposite cicatrices. Leaf scars eight centimeters in length, two centimeters in width, the disks much shorter, only four and a half centimeters long and twelve millimeters broad in the middle. The internal surface of the disks is rough or irregularly punctate and wrinkled lengthwise. The whole stem is covered by a coating of coal one to two millimeters thick, representing the upper surface or bark with the rootlets covering it, but passing aside of the leaf scars. The cicatrices are comparable by their shape to those of Plate LIX, f. 2 ; they are however much narrower, as are also the lateral borders, while the disks being shorter, the space at the lower and upper part is wider. By the coating of rootlets and the distance of the scars it resembles the following species, but the rootlets are thicker and very long, as no trace of points of attachment can be seen upon the stems. From the base of the stem, bundles of leaves of Taeniophyllum decurrens (Plate LXXXI, f. 1) come out, diverging on an acute angle as in the figure, seemingly attached to the rootlets which, however, are narrower in size and cover the stem without divergence. These leaves bearing macrospores have been described with the group of plants doubtfully referable to Lycopodiaceae. Habitat—Cannelton, Pa., recently discovered by Mr. I. F. Mansfield. | |||||
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Scar narrowly oval, obtuse at the base, emarginate at the upper end, borders large, flat and smooth; impressions narrow, confluent at base; horns short curving to the continuous line of the central oval disks; borders scaly. The scar is comparatively narrow, nine centimeters long, a little more than three centimeters broad; scales of the borders nearly one centimeter long, lanceolate acuminate, turned downwards. Habitat—Cannelton, Mr. I. F. Mansfield. | |||||
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Differs from the former species by its smaller size and the borders without scales. The scars are only five centimeters long and twenty two millimeters broad. By their shape, they might be supposed to represent the same species as the former. But no trace of scales is seen, either upon the borders of the scars, or upon the fragment of smooth shale where they are preserved. Habitat—Same as the former. | |||||
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STEMMATOPTERIS PUNCTATA, Lesqx., Plate LIX, Fig. 3.
Scars nearly exactly oval or
slightly obovate; borders flat; internal disks narrow, enlarged
upwards; vascular lines joined at the horns; surface of the bark
punctate the dots representing base of hairs or of scales.Caulopteris punctata, Lesqx., Geol. of Penn'a, 1858, p. 869, Plate XIII, f. 1. This species is closely allied to Stemmatopteris peltigera (Sigillaria, Brgt.). It has larger scars and the bark roughened by larger obtuse tubercles. It is rare and generally found in specimens bearing a number of scars all of the same size as those of the figure. Habitat—Gate Vein, New Philadelphia, Pa. Cannelton, Mr. I. F. Mansfield. Mr. R D, Lacoe has some splendid specimens which seem intermediate in their characters between this species and Stemmatopteris peltigera. This renders the separation of Caulopteris punctata somewhat doubtful. These last specimens are from Oliphant, No. 1 vein and Port Griffith, Pa., F vein. | |||||
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STEMMATOPTERIS INSIGNIS, Lesqx., Plate LIX, Fig. 7.
Scars very large, exactly
ovate; borders large and fat; vascular impressions parallel to the
borders, with curves distant, descending parallel to near the basal
line where they unite, forming a spatulate obtusely. pointed medial rib.Caulopteris insignis, Lesqx., Geol. Rept. of Ill., II, p. 459, Pl. XLIX, f. 1. A very remarkable species represented by the largest and best preserved scar of a fossil Fern-tree seen until now. The bark, which from want of place is not figured here, is smooth; the scar twelve centimeters long, eight and a half centimeters broad, is exactly ovate, with a smooth border two centimeters broad and an internal disk horse shoe shaped with the curve of the horns distant, but the border lines continuing downward and joined only near the base of the disk. On both sides of the branches, near their point of connection and on each side, are marked two narrow lines parallel to the branches and scythe shaped, bordering an internal area irregularly dotted by points apparently the remains of filiform vessels. Habitat—Shale of Duquoin Coal, Ill., two specimens of the same size in the State cabinet. | |||||
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STEMMATOPTERIS GIGANTEA, Lesqx.
Scar large; obovate, with abroad double border; branches of the vascular scars diverging, horns hooked, distant.Caulopteris gigantea, Lesqx., Geol. of Penn'a, 1858, p. 869, Plate XIII, f. 2. The scar is a little more than half as large as the former. Its shape contrary to that of most of the other species is obovate, enlarged upwards; the broad border, twelve millimeters, is distinctly divided into two rings of equal width, the outer apparently thicker. The horns are seven millimeters distant, the line of vascular bundles thick, at least two millimeters. Habitat—The specimen was in the cabinet of Mr. Clarkson, of Carbondale, and figured there in 1852. | |||||
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Scars large, in quincunxial order, about two centimeters distant in oblique direction, nearly round; surface smooth; branches of the disks parallel to the borders, horns distant in half circle. The scars are seven to eight centimeters both ways; the disks, two and a half centimeters broad, are bordered by a deep narrow vascular impression following the same curve and thus parallel to the borders of the scars, with the horns hooked and opposite, the space between the inside curve being six to eight millimeters. The surface of the disks and of the scars is exactly smooth as also the surface of the stem between the scars, marked only by distant small verrucose tubercles; a few of them are seen upon the borders of the cicatrices. Habitat—Oliphant, Pa., Coal No. 1. Specimens in the cabinet of Mr. R. D. Lacoe, of Pittston. | |||||
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Annular scars small, truncate at the top, abruptly contracted near the very obtuse base; disk somewhat enlarged in the upper part, the branches curving at a distance from the borders and descending parallel to near the base of the scar; appendages half round parallel to the upper curves; surface smooth. The disk is, in its shape, remarkably similar to a man's face, the decending branches of the inside impressions having, in their parallel disposition, the shape of a nose and the lines under the curves that of the eye brows, while the lower part of the ring is abruptly narrowed into the shape of a broad chin. The scars are about four centimeters long and nearly as broad. Habitat—Cannelton, Pa.. Mr. I. F. Mansfield. | |||||
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Outside rings transversely oval; internal scars rounded at the base, enlarging upwards in diverging branches, abruptly curved inside and joined in the middle in transversally oval knots or horns; surface very smooth polished. The scars are transversely oval, four and a half centimeters broad, three centimeters in vertical length, joined by the borders in spiral order, like the scars of Lepidodendron. The inside disks, kidney shaped in outline, are formed by deep vascular lines, at first curving upwards in opposite directions, then abruptly bending towards each other and joined by transversely hooked horns, the lateral branches projecting beyond the capping line of the disks, which are two centimeters broad in the upper part, one and a half centimeters in vertical direction. The specimen is regrettably too small, a piece of bark of an apparently young tree, the epidermis being very thin and remarkably smooth. Habitat—Cannelton Coal, Mr. I. F. Mansfield. | |||||
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STEMMATOPTERIS WORTHENII, Lesqx.
Caulopteris Worthenii, Lesqx., Geol. Rept. of Ill., II, p. 459, Pl. L, f. 1. Stem slender; scars very distant, rounded at the base, narrowed upwards; internal impressions horse-shoe shaped, with horns converging; vascular scars varallel to the borders, marked above the base by a semi-lunar appendage. The stem seven to eight centimeters in the widest diameter, reduced by compression or flattened to half this thickness, bears four distant scars, one of which only is well preserved. It is four centimeters long, two and a half centimeters broad, contracted above to an emarginate apex only five millimeters broad. The scars are about twenty-five centimeters distant in vertical line. The vascular impressions, following parallel to the flat outline of the borders, are slightly narrowed to the upper part, curved into two confluent horns, the line of connection descending lower, or nearly to the middle of the scar. The impressions are more or less obliterated by erosion, one of them being exactly elliptical and all without dots or traces of cylindrical vessels. Habitat—Carmi, White county, Ill., upper coal measures. | |||||
| Caulopteris, Ll. and Hutt. Scars with the inside disk either marked by linear bands, remains of
vessels passing from the trunk to the base of the rachis, or covered by
impressions of rootlets obliterating its shape, or merely ovate or
elliptical, without traces of horse shoe shaped vascular lines. These
lines may have been, in some cases, effaced by abrasion of the surface
or covered by rootlets.
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Stem originally cylindrical, half flattened by compression; scars in longitudinal series, large, subcontinuous, elliptical, marked lengthwise by longitudinal deep impressions. The specimen is a silicified stem, seventeen centimeters broad, reduced by compression to a thickness of four centimeters in the middle. The scars, six and a half centimeters long, three and a half broad, are regularly elliptical, deeply grooved into the stone, marked by longitudinal elevated narrow ribs, which, when destroyed, leave the surface under them nearly smooth. The bark between the scars is thick, about one millimeter, verrucose, the warts generally directed lengthwise and oval. The internal structure is indistinctly seen, Plate LX, f. 2, in woody fasciles of dark color, linear, flexuous, irregularly divided. diversely mixed in the cellular tissue, somewhat disfigured by compression. The disposition of the vessels is like that figured by authors from species of Psaronius, comparable especially to Psaronius pulcher, Corda, Beitr., p. 96, Plate XXIX, f. 5. The species is closely allied to Caulopteris Phillipsii, Ll. and Hutt., II, Pl. 140, differing by the shape and size of the scars, longer and narrower, joined by a narrow neck. Habitat—This beautiful specimen was kindly presented to the survey by Mr. Wm. Gifford, as found in the coal measures near Alta, Peoria county, Ill. | |||||
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Fragments of a flattened stem, one hundred and fifty centimeters long, twenty centimeters in diameter, with four longitudinal rows of alternate ovate scars, six to seven centimeters long, four to five broad, at an average distance of one and a half to two centimeters, both ways, marked lengthwise with regular vertical stria, evidently remains of linear bundles of vessels, independent of the flexuous strive, impressions of rootlets which cover the surface of the bark between the scars. No traces of vascular impressions are seen, except two lines curving downward, in an obtuse angle of divergence from the middle of the disk. The outside ring is narrower in the upper part; the shape of the scars, twice as broad near the base as near the top, is exactly ovate. I refer to the same species another specimen with scars exactly round, much smaller, placed in the same relative position, not quite as distant, covered like the bark with flattened rootlets, under which is obscurely seen a central disk like a horse-shoe shaped vascular impression. It may represent a different species. Habitat—Both specimens are in the cabinet of Mr. R. D. Lacoe, obtained from coal No. 1 of Oliphant. | |||||
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CAULOPTERIS OBTECTA, Lesqx., Plate LIX, Fig. 8.
Stems of small size, covered
with linear roots; scars generally distant, elliptical ; disks obsolete
by the covering of the rootlets.Geol. Rept. of Ill., IV, p. 457, Pl. XXVIII, f. 1-4. The filaments, remains of flattened rootlets, three millimeters in diameter, exactly linear, are seen derived from under the bark, where they leave small or narrowly oval scars at their point of attachment. By their superposition and compression, they cover the stem by a coating of carbonaceous matter more than one millimeter thick. The scars have all been covered by these radicles after the falling off of the petioles, and therefore, though their outline is perceivable, the internal disk is indistinct: Even after abrasion of the coaly surface, the impressions of the radicles leave irregular vertical lines, merely interrupted towards the top of the disk, as seen in the figure which is reduced to one fourth the size of the specimen. The vertical distance between the scars is very great, sixteen centimeters. On another specimen, whose scars are not quite as large, four and a half centimeters long, three and a half broad, the distance is reduced to eleven centimeters. As seen from the specimen, the distance is very variable, even upon one and the same fragment of stem. Habitat—Shale of the coal of Morris, Ill. The specimen figured is in the Museum of Comp. Zool. of Cambridge. Cannelton, Penn'a, in fine specimens—Mr. I. F. Mansfield. | |||||
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CAULOPTERIS CISTII, Brgt.
Stem large, surface covered
with adventive rootlets descending between the scars which are placed
in quincunxial order, vertically distant; internal disk narrowly
elliptical, a little broader at the base, slightly emarginate at the
top; surface clotted, rugose.Sigillaria Cistii, Brgt., Hist. d. veg. foss., p. 418, Pl. CXL, f. 2. Caulopteris Cistii, Gein., Verst., p. 31, Pl. XXXIV, f. 1, 2. Lesqx., Geol. of Penn'a, 1858, p. 869. Stemmatopteris Cistii, Corda, Beitr., p. 76. Schp., Paleont. veget., p. 710. The border of the scars is large, but often partly covered or obliterated by the impressions of rootlets which fill the lateral space between the scars, while under them the surface is left uncovered of radicles or smooth, for half or even for the whole distance between them. The vertical distance is not less than twelve centimeters, sometimes much greater. With the ring the impressions average six to seven centimeters long, and a little more than two and a half centimeters broad. The internal disk is generally narrowly elliptical, obtuse at both ends, sometimes also emarginate at the upper end, as by horse-shoe shaped vascular impressions. From this character, the species should be described as Stemmatopteris. But the disks are rarely distinct, and the whole surface is very rugose lengthwise, as dotted by irregularly round, even linear impressions of small fasciles of vessels. All the specimens examined are flattened or generally large pieces of bark, except the following. This one, in the Museum of Comp. Zool. of Cambridge, is a fragment of a slender, cylindrical, slightly compressed stem, nine centimeters in the widest diameter, flattened to five and a half centimeters, marked by elliptical scars, ten centimeters long, only two and a half broad, obtusely pointed at both ends, with central disks shorter and placed towards the upper part of the scars. The specimen, which I labeled Cyclopteris elongata, Sp. nov., may be a variety of Caulopteris Cistii, though the surface of the stem is smooth and without radicles. This last difference is not of specific value, for the adventive radicles seen upon many species of Fern-trees of our time, generally cover the base or the lower part of the trunks, even as high up as the middle, but gradually disappear towards the top. Habitat—The species is not rare in the coal measures. Found at Cannelton, by Mr. I. F. Mansfield; at Oliphant, by M. Jones, No. 1 vein; at Pittston, E vein of Port Griffith, Mr. R. D. Lacoe; also in the coal shale of Morris, Ill., etc. The specimen of the Museum of Comp. Zool., is from Cambridge, Ohio, Upper Coal Measures. | |||||
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Scars large, oval, oblique,
close; borders very broad, formed of a double ring; internal disks
convex, oval, rounded at the base, obscurely emarginate or truncate at
the top; surface deeply striate by impressions of flexuous rootlets,
filling all the space between the scars. Differs essentially from Caulopteris Cistii, by the close position and the large size of the scars, with borders formed of a double ring, more than one centimeter broad, the outer part smooth, the inside more or less rugose or dotted, six to eight centimeters distant only, in vertical direction. The two specimens which I have seen of this species show the scars oblique to the vertical plane of the axis. Habitat—Cannelton, Pa.; Mr. I. F. Mansfield. | |||||
The descriptions of the following species, from the North American Devonian, are copied from Prof. Dawson. | |||||
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Trunk two to three inches in diameter, longitudinally rugose; leaf scars broad, rounded above and radiatingly rugose, with an irregular scar below, arranged spirally in about five ranks; vascular bundles not distinctly preserved; petioles slender, much expanded at the base, dividing at first in a pinnate manner, and afterwards dichotomously; ultimate pinnae with remains of numerous apparently narrow pinnules. The author remarks that the specimens allow him, at least, to conjecture that the trunks may have belonged to Fern-trees, although none of them are sufficiently perfect for description. Habitat—The Chemung group, near Gilboa, New York. | |||||
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Flattened stem about eighteen
inches long, three and a half in average breadth; the exposed side
shows about twenty-two large leaf scars, arranged spirally, each leaf,
when broken off, has left a rough fracture; and above this there is a
semi-circular impression of the petiole against the stem, which, as
well as the surface of the bases of these petioles, is longitudinally
striate and tuberculated; the structures are not preserved, but merely
the outer epidermis as a coaly film. Habitat—Marine limestone, containing Brachyopods, Trilobites, etc., of the corniferous limestone of Ohio. | |||||
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The upper part of the specimen,
eight centimeters in diameter, about thirty centimeters in length,
shows thirty leaf scars, about two centimeters wide, and rather less in
depth; the upper part of the scars presents a distinct and sometimes
double marginal line, sometimes with a slight depression in the middle.
The lower part is irregular, and when most perfect, shows seven slender
vascular bundles, passing obliquely downward into the stem. The lower
perfect leaf bases have the structure preserved and show a delicate
thin-walled oval parenchym, while the vascular bundles show scalariform
vessels, with short bars in several rows, in the manner of many modern
Ferns; some of the scars show traces of the hypocrepian marks,
characteristic ofProtopteris , and the arrangement of the vascular
bundles at the base of the scars is the same as in that genus, as are
also the general forms and arrangement of the scars. A second specimen is covered with a mass of flattened aerial roots, these being parallel to each other in the manner of the Psaronites of the coal formation. Habitat—With the former. | |||||
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Scars large, round-quadrate in outline, mostly contiguous, placed in opposite biserial rows; internal disks convex, with central or vascular impressions in the form of a horse shoe, or a medial band dividing the disks into two lobes, joined in the middle. The disposition of the petioles in two opposite rows and close to each other is very peculiar, and not seen in any Fern-trees of the present time. | |||||
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MEGAPHYTUM McLAYI, Lesqx.
Scars large, nearly square in
outline, contiguous or somewhat distant; borders flat, large, smooth,
internal disks deeply emarginate at the top and deeply cordate at the
base by the vascular line passing up and down to near the middle; bark
of the trunk smooth.Geol. Rept. of Ill., II, p. 458, Pl. XL VIII. Schp., Paleont., veget., I, p. 715. From two good specimens, one in the collection of the Museum of Comp. Zool. of Cambridge, the other communicated by Mr. Mansfield, I am able to see exactly the characters of the disks, and the essential differences which separate the species from the following. The scars, twelve centimeters long, nine broad, including the flat borders, are square in outline, rounded at the corners. The borders average two centimeters in width, being a little narrower on the sides. The disks are seven centimeters broad at the enlarged rounded deeply cordate base, gradually narrower toward the round top, which is also deeply emarginate or obcordate by the vascular impressions. These, curved in horse-shoe, enter the disk both at the upper and lower part, by branches or linguiform appendages which divide it nearly to the middle. In the figure of the Geol. Rept. of Ill., l.c., the division appears continuous from the top to the base of the disks; but the specimens first obtained and copied were not in as good state of preservation as those I have received since. The borders of the scars are not always contiguous; sometimes there is a distance of three to four centimeters between the scars, as seen in a specimen from Morris. The epidermis of the bark is smooth or without tubercles. Habitat—First discovered in the coal of St. John, Ill., by Mr. John McLay. The specimen of Cambridge, presented to the museum by Dr. Hand, is from Morris. The third is from Cannelton, found by Mr. I. F. Mansfield. | |||||
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MEGAPHYTUM GOLDENBERGII, Weiss—Plate LXI, Fig. 4.
Scars transversely oral, joined
by the borders, obscurely divided into two rings by a parallel thin
line; disks of the same form, marked by small irregular perforations,
especially near the base; central disks small, deeply obcordate; bark
tuberculate.Weiss, Zeitsch. d. deutsch. geol. Gesellsh., XII, 1860, p. 510. Schp., Paleont., veget. I, p. 713, Pl. LV. Schimper, l.c., has two splendid figures of this species, showing both sides of a specimen forty-three centimeters long and thirty centimeters broad, flattened. The scars of the American specimen, which is represented partly in Atl., are larger, eleven centimeters in horizontal direction, and six centimeters in vertical line. The shape of the scars and of both the internal and outside disks are exactly the same. The internal disk is comparatively small, also transversely oval, three centimeters in the horizontal direction, half as wide in the other. The surface is somewhat obliterated by compression, and the division of the internal disk is obscure. It is marked in Schimper's figure as nearly split or deeply emarginate by the vascular impressions descending linguiform to below the middle. The tubercles of the bark are irregularly conical, perforated or funnel-shaped in the centre; they are obscurely reproduced by concave impressions upon the borders and the disks. Megaphytum magnificum, Daws., Quat. Journ. Geol. Soc., vol. XXII, Pl. VIII, f. 34, from the coal of the Joggins, Canada, is closely allied to this species. Habitat—Shale of the Clinton coal, Mo.—Dr. I. H. Britts. | |||||
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Trunk large, covered with
appressed adventive radicles derived from oval tubercules irregularly
placed upon the stems. Scars large, contiguous, transversely oval;
disks broad, of the same form, the lower and lateral borders parallel
to those of the scars, horse-shoe shaped at the top, or curved in two
horns, the lines, fasciles of vascular bundles, descending by a slight
divergence to near the base of the disks, there connected by a
crescent-shaped line forming a spatulate tongue; appendages distinct,
nearly joined to the middle of the tongue, diverging outward in
descending and abruptly curving inward to near the base of the tongue;
surface of the disks and scars marked by irregularly scattered
verrucose obtuse smooth mamillae of various size, more numerous on the
insides of the disks. The fragment represents part of a flattened. stem, thirty centimeters in diameter, one side of which only is seen. The scars measure transversely ten to eleven centimeters and vertically six; the borders are continuous, without line of separation between them. The disks seven centimeters broad laterally, four in vertical direction, follow in a broad curve and parallel to the borders of the scars, to the upper part, where the lines of the vascular bundles curve and pass nearly straight toward each other, bending abruptly downwards when at a distance of one centimeter and descending with a slight divergence toward the base of the disks where they are joined by a broadly obtuse line of connection. The shape is exactly horse-shoe shaped, the medial tongue descending as low as in Stemmatopteris insignis, Plate LIX, f. 7 and being of the same shape, only more enlarged and more obtuse at the base. On both sides and as seen also upon that same figure, l.c., the tongue is bordered from below the middle by two appendages which, coming out from below the middle of the tongue, rapidly diverge from it to one and a half centimeters distance and then abruptly curve inward toward the base, effacing before reaching it. Of a different shape they represent the appendages at the base of the tongue of Plate LIX, f. 7. The surface of the disks and scars is quite smooth, except for the tubercles, which, few and distant upon the border of the scars, are numerous in the inside of the disks, equally distributed also, but less distinct upon the surface of the tongue. The trunk, outside of the scars, is covered with closely appressed flattened radicles averaging three millimeters in diameter. They seem derived from numerous pustulate scars, four to five millimeters long, half as broad, irregularly placed upon the stem. The annular scars of this Fern have a close affinity of character to those figured, without specific name and description, by Grand'Eury, Fl. Carb., Pl. XIII, f. 3. The scars and disks are much larger in the American form; the distance between the disks at least twice as great, two and a half centimeters; the vascular lines forming the tongue are not parallel, but diverge toward the base and descend lower; the radicles, as seen upon the figure given by the French author, are much larger. But this character may not be worth considering. If the nature of Megaphitum was not already definitely ascertained to be that of a Fern-tree, this species, by the identity of the characters of the disks with those of Stemmatopteris, would sufficiently prove its close relation to this genus. Considering merely the scars of Tree-ferns, as we have them for the specific determination of these plants, there is scarcely a definite line for generic division between them. Habitat--Oliphant No. 1 vein Mr. Williams; the cabinet of Mr. R. D. Lacoe. | |||||
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Scars gibbous, square-oval,
rounded at the base, slightly emarginate at the top where the
transversely broad ovate disk is placed; vascular impressions
horse-shoe shaped or reniform, with horns curved up and hooked. The specimen is represented upside down, as remarked by Prof. Schimper. The central disk and vascular impressions should, therefore, be described as basilar with horns turned up. The space between the base of the scars and the disk is, however, much inflated, and seems to show the lower descending part of a petiole rather than the facing of its internal part. The same disposition as that of this figure is remarked in Megaphytum frondosum, Artis., Antedil. Phytol., Pl. XX, a species to which this one is related by the form of the scars and the striate surface of the bark. It is however in contradiction to what is known of the direction of the vascular impressions, in living Ferns. The scars including a narrow border are six and a half centimeters long, four centimeters broad in the middle. The disks whose outlines are somewhat obscure and blended with the underneath inflated bolsters, are two and a half centimeters, transversely, and only two and a half in vertical direction. The branches of the reniform impressions are two centimeters apart, curved and hooked at a distance from each other, with an indistinct irregular round or oval scar in the middle. The specimen bears eight contiguous scars; the bark is irregularly striate lengthwise. Habitat—Carmi, White County; specimen in State cabinet of Illinois. | |||||
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To this genus are referred stems of Tree-ferns, covered in the inferior
part by adventive roots, increasing by their superposition the conical
base of the trunks. The cortex is thick, parenchymatose; the woody
cylinder is subdivided into branches composed of fascicles of vessels,
either half cylindrical or diversely plicate, immersed in the cellular
medullar tissue. These vascular bundles affect in their curves and
subdivisions very variable dispositions, as may be seen in the cross
sections, Plate LX, f. 2. The specific characters are recognized by the
analysis of the internal structure, made on silicified cross sections,
by the cutting and polishing of thin lamellae. They are too different
and varied to be understood without figures; and though I have
collected a considerable number of specimens of those trunks of Psaronius,
I have not been able to obtain the necessary assistance of a lapidary
for their specific identification. They abound, as remarked already, in
the Sandstone (Mahoning) of Southern Ohio, on Shade river, and in
Kentucky along the lower Kanawha river. The adventive roots which cover
the cortical parenchyma of the stem, even enter it and. become part of
it, are often found expanded at the base of the trunks and compressed
in large flattened stumps of very irregular shape, with a conical
medial projection, base (mostly destroyed) of the stems of which they
were the supports. The same arrangement of adventive rootlets,
surrounding the base of Fern-trees increasing in thickness and in
strength as fast as the trees ascend higher, is seen on species of
Tree-ferns of our time. The trunks of Shade river vary in thickness
from ten to thirty centimeters; rarely are they found smaller but
sometimes larger. For I obtained from that locality a remarkably well
preserved cylindrical trunk, two feet in diameter which is now in the
Museum of Comp. Zool. of Cambridge. The cabinet of Dr. Hildreth, presented to the college of Marietta, Ohio, has some pf these stems of Psaronius polished in transverse sections. Even some have been prepared as deck-boards of small tables, forming, in their arrangement, variegated and beautiful designs, according to the peculiar distribution and shape of the vessels, as distinct upon the polished surface as might be the venation of marble. | |||||
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