PROCEEDINGS
OF THE TOMSK ORDER OF THE RED BANNER OF LABOR POLYTECHNIC
INSTITUTE named after S. M. KIROV

Vol. 127, issue 2
1964

SOME NEW WOODS

FROM THE PERMIAN DEPOSITS OF THE KUZBASS

M. D. PARFENOVA

(Presented by Prof. Dr. L. L. Khalfin)

Fossil woods have long attracted the attention of paleobotanists. A great deal of material has been accumulated on woods of Meso-Cenozoic age. As for Upper Paleozoic woods, their systematic study has not yet begun, although the stratigraphic value of this material is undoubted. The history and, in part, the methods of investigation of Upper Paleozoic woods of the Soviet Union were given by us earlier (see the preceding issue of the Proceedings of TPI); therefore, in the present paper we give only descriptions of new genera and species discovered by us in studying a collection of petrified woods gathered by the author in deposits of the Kolchugino Series of the Kuzbass.

Genus Belovskoxylon gen. nov.

Annual rings 2–4 mm wide; under the microscope the boundary of the annual ring is rather even, sometimes distinct, sometimes poorly discernible. The cells of the spring and summer wood differ more in shape than in size: the spring cells are rounded, quadrangular, without definite shape, with sinuous thin walls; probably they were large, thin-walled, and easily yielded to mechanical influences, since the cells of the spring part of the ring are usually strongly deformed. The summer cells are of more regular rounded-quadrangular outline. The transition from spring cells to summer cells is usually gradual, but sometimes also abrupt, so that a certain boundary is marked within the ring.

The pits are bordered, contiguous, rounded-polygonal, somewhat elongated in width; in the tracheids they are arranged in 1–2 rows; moreover, when arranged in one row in the tracheids, the pits lose their polygonal form and, being somewhat elongated in width, acquire transversely oval outlines.

Belovskoxylon cyclicus sp. nov.

Plate 1, figs. 1–5.

Type species. Collection of the Tomsk Polytechnic Institute, specimen 17. Kuzbass, Belovo district, area of the field of the “Pionerskaya” mine, borehole 256, depth 187 m. Kolchugino Series.

Diagnosis. Transverse section. Macroscopically the growth rings are distinct, their width 2–4 mm.

Under the microscope: the boundary of the growth ring is fairly even, sometimes sharp, sometimes not very distinct. The spring and summer cells of the ring differ not so much in size as in form. The spring cells are rounded-quadrangular, more often unpitted, with sinuous thin walls; apparently these cells were likewise rounded-quadrangular, but had thin walls and were easily subject to deformation. The spring cells are arranged rather densely and measure up to 58 μ along the greatest diameter. Gradually, and sometimes rather abruptly—so much so that a boundary is marked within the ring—the cell walls become less sinuous and the cells acquire more regular rounded-quadrangular outlines. The cell walls continue to remain thin. Only at the very end of the growth ring do the cell walls thicken slightly. The cells themselves become smaller—11.6–29.2 μ wide and 6–34.8 μ long. The cells here are the most distinct, square, quadrangular, rounded, sometimes flattened radially.

The medullary rays are fairly frequent and extend within one or two growth rings; at the boundary of the growth ring, 6–11 rays are counted across the diameter of the microscope field of view. As a rule, the rays are refracted twice in the growth ring: once at the boundary of the growth ring—more sharply—and a second time at the transition from early-spring cells to summer cells. In the latter case the bending of the rays is sometimes slight; this depends on the degree of distinctness of the boundary at the transition from spring cells with sinuous walls to summer cells with more even walls. The rays in the late-summer layer of cells are rectilinear or slightly curved. In the spring and early-summer layer, where we observe cells with sinuous walls, the rays are finely undulate. The refraction of the rays at the indicated boundaries, as well as their wavy character, is most likely due to a mechanical phenomenon: displacement of the layers of cells relative to one another along the cambium.

Tangential section. Tracheids 11.6–46.4 μ wide, with even or slightly incised walls and long pointed ends.

The medullary rays are rather frequent; in the field of view of the microscope there are 26–30 rays. The rays are uniseriate and biseriate, consist of 1–16 cells in height; the bulk of the rays consists of 3–6 cells; rays of 9 cells occur more rarely, and rays of 16 cells in height are extremely rare. The ray cells are oval or elongate-oval; their height is 17.4–34.8 μ, their width 6–23.4 μ. Biseriate rays occur very rarely; the second row may consist of only 1–2 cells.

In the walls of the tracheids, pores are visible, located on the radial walls. Sometimes rounded-polygonal light pieces of resin occur.

Radial section. Tracheids 17–40.6 μ wide, with even or slightly incised walls. Narrow tracheids are usually wavy. The ends of the tracheids are sometimes bluntly pointed and often converge in a bundle or intertwine in the form of a herringbone; this is especially characteristic of narrow tracheids.

The medullary rays consist of elongated barrel-shaped cells 11.6–29.2 μ high and 75.4–116 μ long.

The bordered pits are arranged in 1–2 rows in the tracheids; they are rounded-polygonal, somewhat extended in width, and closely spaced. In narrow tracheids the pits are usually arranged in one row in the middle of the tracheid. In the latter case the pits lose their polygonal outlines and, being in close contact with one another, are somewhat extended in width—oval. Their dimensions are small, about 11.6 μ in diameter. The apertures of the pits are rarely round, more often oval, and obliquely arranged.

Distribution. Kuzbass: Belovskii district, area of the “Pionerskaya” mine field, borehole 256, depth 187 m; Nikitinskoe deposit, borehole 2482, depth 97 m, Kolchugino Series.

Genus Leninskoxylon gen. nov.

The annual rings are distinct, even, 1.5–2.5 mm wide. Under the microscope the boundary of the annual rings is sharp and rather even. The cells of the spring wood are distinct, large, square, quadrangular, or slightly rounded. Gradually decreasing in size, the spring cells pass into the late-summer cells. The latter are flattened in the radial direction, and their lumina often become slit-like.

The pores are bordered, rounded-polygonal, close together, and are arranged in the tracheids in 2–4 rows.

Leninskoxylon doliformis sp. nov.

Plate II, figs. 1–3; Plate III, figs. 1–5

Type species. Collection of the Tomsk Polytechnic Institute, specimen 3. Kuzbass, Leninskii district, borehole 2450, depth 10.42 m. Kolchugino Series.

Diagnosis. Transverse section. Macroscopically: the annual rings are clearly expressed, their width 2–2.5 mm.

Under the microscope: the boundary of the annual rings is sharp and rather even. The cells of the spring wood are distinct, large, square, quadrangular, slightly rounded, measuring 34.8–81.2 μ in length and 34.8–58 μ in width. The cell walls are even, or slightly curved, up to 6.5 μ thick. Such cells rather gradually decrease in length, become radially flattened, and their form is quadrangular or slightly rounded. At the very end of the annual ring the cell lumina often become slit-like. The width of the late-summer cells is predominantly 34.8 μ, their length up to 11 μ. The thickness of the cell walls is approximately the same throughout and equals 6.5 μ. Occasionally in the annual ring there are groups of cells with sinuous walls. Usually such groups of cells are confined to the second half of the annual ring and are often maintained concentrically.

The medullary rays are rather rare, but 4–5 rays are counted in the field of view of the microscope. The rays are rather long; a single ray extends over 2–5 annual rings. The rays pass through the boundary of the annual ring in a straight line, but where groups of cells with sinuous walls occur, the rays, entering them, curve and themselves become sinuous.

Tangential section. Tracheids 23.4–58 μ wide, long, with even walls and short, bluntly rounded ends. Very rarely, single cross-walls occur in the tracheids.

The medullary rays are rather rare; in the field of view of the microscope 7–13 rays are counted. The rays are uniseriate and consist of narrow and tall oval cells. The dimensions of the latter are 5.8–23.4 μ in width and 29.2–34.8 μ in height. Sometimes the cells of the rays are almost slit-like. The rays consist of 2–7 cells in height, but the main mass of rays consists of 4–5 cells in height.

The bordered pores, situated on the radial walls of the tracheids, gradually show through also in the tangential section; they are rounded-polygonal. The pore apertures are round or oval, arranged

in the transverse, and more often oblique, direction; pore size about 11.6 μ in diameter, pore apertures up to 5 μ long.

Radial section. Tracheids 23.4—92.8 μ wide, with even or pitted walls, with pointed or bluntly rounded ends. The ends of the tracheids are often bent; sometimes the blunt ends of opposite tracheids are opposed.

The medullary rays consist of elongated quadrangular or barrel-shaped cells. The dimensions of the ray cells are 29.2—58 μ in height and 58—116 μ in length; oblique partitions are sometimes observed between ray cells.

The pits are bordered, arranged in 2—4 rows in the tracheids, and have rounded-polygonal outlines, up to 12 μ in diameter. The pore apertures are round or oval, usually arranged in an oblique direction, more rarely in a transverse direction. In the crossing fields the pits are simple, round or oval, 3.7—4.9 μ along the greatest diameter.

Comparisons. See the description of the species L. diplostichus sp. nov.

Distribution. Kuzbass, Leninsk district, borehole 2450, depth 10.42 m. Kolchugino Series.

Leninskoxylon diplostichus sp. nov.

Pl. IV, figs. 1—4; Pl. V, figs. 1—4

Type species. Collection of the Tomsk Polytechnic Institute, No. 18. Kuzbass, Leninsk district, borehole 2456, depth 692 m. Kolchugino Series.

Diagnosis. Radial section. Macroscopically: the annual rings are expressed rather clearly; their width is approximately 1.5—2 mm.

Under the microscope: the boundary of the annual rings is distinct and rather even. The spring cells are quadrangular, square, rounded; their dimensions are 17.4—58 μ in width and 23.4—58 μ in length. Gradually the cells decrease in size and pass into the latewood. The latter are flattened in the radial direction and their lumina are often slit-like; dimensions: 23.4—34.8 μ in width, up to 11 μ in length. The width of the layer of latewood cells varies; sometimes it is small.

In some places groups of cells with sinuous walls occur. Such groups are sometimes rather consistently concentric and occur more often in the second half of the annual ring. The thickness of the cell walls is approximately the same and equals 10—12 μ.

The medullary rays are frequent; across the diameter of the microscope field of view at the boundary of an annual ring, 6—9 rays are counted; they are of different length, some end within one ring, others extend through 2—4 rings. The rays are rectilinear; they cross the ring boundary without changing direction or bend only slightly. But when entering groups of cells with sinuous walls, the rays are refracted.

Tangential section. Tracheids 11.6—46.4 μ wide, with even walls and, in most cases, with long-pointed ends.

The medullary rays are frequent; 31—37 rays are counted in the microscope field of view. They consist of 1—14 cells, but in the main they consist of 7—10 cells. The ray cells are round or slightly oval. The dimensions of the ray cells are 11.6—34.8 μ in width and 17.4—34.8 μ in height. The rays are predominantly uniseriate, but rudiments of biseriate rays also occur; the cells in such rays are arranged not oppositely, but alternately. Sometimes the second row of a ray consists of only one cell. In the walls of the tracheids, pores are visible, arranged on the radial walls.

Radial section. Tracheids from very narrow to 58 μ wide, with even or indented walls, with pointed, and sometimes with blunt and bent ends.

The medullary rays consist of quadrangular, elongate-oval cells 17.4—46.4 μ high and 81.2—175.6 μ long. Very rarely, oblique partitions occur between the cells of the rays. The pores are bordered, rounded-polygonal, slightly elongated in the transverse direction. The pores are arranged in the tracheids in 2—3 rows; they are crowded, and the pore apertures are round or oval to slit-like, positioned in the transverse direction.

Comparison. The present species is very close to the described species L. doliformis sp. nov. of the same genus. These species differ in the character of the medullary rays in radial section: in the preceding species the cells are exclusively elongate-oval; in the species described here the ray cells are strictly quadrangular and even square, while elongate-oval cells occur extremely rarely.

Distribution. Kuzbass: Leninsky district, borehole 2456, depth 692 m; Nikitino deposit, borehole 2482, depths 252, 70 m.

Genus Microxylon gen. nov.

This genus includes woods with narrow annual rings, 0.5—1 mm wide. The boundary of the annual rings is not very distinct under the microscope. The cells of the spring wood have sinuous walls and are usually strongly deformed. The latewood cells are quadrangular, stretched in width. The pores are bordered, crowded, rounded-polygonal in outline, and are arranged in the tracheids in 2—3 rows.

Microxylon debilis sp. nov.

Pl. VI, figs. 1—5; Pl. VII, figs. 1—4

Type species. Collection of the Tomsk Polytechnic Institute, specimen 11. Kuzbass. Leninsky district, Zainsky area, borehole 2490, depth 109.70 m. Kolchugino Series.

Diagnosis. Transverse section. Macroscopically the annual rings are expressed; their width is approximately 0.5—1 mm.

Under the microscope. The boundary of the annual ring is distinguished with difficulty, but is sometimes more distinct and has a slightly sinuous character. The spring cells are distinguished by strongly indented walls and are rather dense. Their dimensions are 34.8—75.4 μ along the line of greatest length. In the transition to summer wood, the cells change not so much in their dimensions as in their form: their walls become less sinuous, and at the very end of the annual ring there is observed a small row of quadrangular cells, slightly flattened in the radial direction, almost with straight walls. The dimensions of these cells are 23.4—34.8 μ in length and 23.4—52 μ in width.

The medullary rays are straight in the layer of latewood cells and sinuous in the spring layer. At the boundary of the annual ring the rays bend; they also bend to one degree or another in the transition from spring wood to summer wood. At the ring boundary, 6—9 rays are counted across the diameter of the microscope field. Both long and short rays occur. Some extend through 2—7 annual rings; others are located only within the limits of a single annual ring.

Tangential section. Tracheids 17.4—46.4 μ wide, with even, more rarely slightly sinuous, walls. Narrow tracheids are sometimes wavy. The tracheids are long, their ends pointed.

Medullary rays are uniseriate, fairly frequent, 18–30 and more in the field of view of the microscope; they consist of 1–10 cells, but the main mass of rays consists of 2–6 cells. The ray cells are small, oval, rounded; their dimensions are 11.6–23.4 μ in width and 17.4–29.2 μ in height. Despite the fairly large number of rays, the small size of the latter and the character of the cells composing them often create the impression of a poorly developed ray system.

The bordered pits are contiguous, small, up to 8 μ in diameter, round or polygonal; they are situated on the radial walls, but are constantly visible also in tangential section.

Radial section. The tracheids are long, with pointed ends and with smooth or serrated walls, 23.4–81.2 μ wide.

The medullary rays consist of long quadrangular cells, constricted at the septa. The height of the ray cells is 17.4–29.2 μ, their length approximately 81.2–139.4 μ.

The bordered pits are contiguous, small, up to 8 μ in greatest diameter. The outlines of the pits are rounded, rounded-polygonal, often slightly elongated in width; they are arranged in the tracheids in 2–3 rows. The pit apertures are rounded, slit-like, oriented transversely or obliquely. In the cross-fields the pits are simple, oval, oriented across the tracheid.

Remarks. In latewood the rays are most densely arranged, but their dimensions are smaller; here they are predominantly two- to four-celled. The greatest number of rays is counted precisely in such areas, but rays with the largest number of cells occur in spring wood. In different specimens the distinctness of the boundary of the annual rings and their width relative to one another also vary, although in general the width of the annual rings is small.

Distribution. Kuzbass, Leninsk district, Nikitinsky area, borehole 2478, depth 117; Proektny area, borehole 2456, depth 283; Zainsky area, borehole 2490, depth 109.70 m. Kolchugino series.

Microxylon heteromerus sp. nov.

Table VIII, figs. 1–5

Type species. Collection of the Tomsk Polytechnic Institute, specimen No. 4, Kuzbass, Nikitinskoe deposit, borehole 2480, depth 73 m. Kolchugino series.

Diagnosis. Cross section. Annual layers are expressed; their width is 1.5–3 mm.

Under the microscope: the boundary of the annual rings is indistinct; sometimes it is even difficult to establish. It is either straight or slightly sinuous. Spring cells with strongly sinuous walls, without definite outlines, more or less gradually pass into cells of rounded-quadrangular outline, 23.4–58 μ in greatest diameter. Cells of the described character rather quickly pass into latewood—quadrangular, flattened in the radial direction. Their dimensions are 23.4–46.4 μ in width and 11.6–3 μ in length. Not infrequently the very last cells of the annual ring are so flattened in the radial direction that their lumina constitute only slit-like openings. The cell walls in all cells are thick, up to 23.5 μ.

The medullary rays are few: 3–6 at the boundary of an annual ring across the diameter of the microscope field of view. The rays are long, extending over 2–5 annual rings. In spring wood the rays are sinuous; in latewood they are more or less straight.

At the boundary of the annual ring the rays bend; sometimes secondary bends of the rays are observed in the spring layer of cells as well.

Tangential section. Tracheids 23.4–46.4 μ wide, with even, less often with slightly indented walls and long-pointed ends.

Medullary rays are rather rare, 12–16 rays in the field of view of the microscope. The rays are uniseriate, consisting of 1–8 cells. The greatest mass of rays consists of 2–4 cells. Ray cells are oval, rounded, very rarely barrel-shaped. Cell dimensions 17.4–29.2 μ wide, 23.4–46.4 μ high.

Radial section. Tracheids with even, rarely with slightly sinuous walls, long, with long-pointed ends. Width of tracheids 11.6–58 μ.

Medullary rays consist of quadrangular cells, sometimes slightly narrowed at the transverse partitions, and therefore the cells are slightly elongate-barrel-shaped. Cell length 81.2–116 μ, their height 23.4–46.4 μ.

The bordered pits are arranged in 2–3 rows in the tracheids, are close together, and have rounded-polygonal outlines; their size is up to 11.6 μ in diameter. The pit apertures are round or oval, obliquely arranged.

Remarks and comparisons. In tangential section, pits located in the radial walls of the tracheids are faintly visible. They are round, contiguous, sometimes with a barely noticeable punctiform round aperture.

In its structure the species described is very similar to M. debilis sp. nov. from the same genus, but it differs strongly from it in the structure and number of medullary rays, and also in the dimensions and structure of the bordered pits.

Distribution. Kuzbass, Leninsk District, Nikitinskoye deposit, borehole 2480, depth 73 m.

Genus Gigantoxylon gen. nov.

Annual rings are well expressed, their width 1.5–5 mm. The summer part of the annual ring constitutes its denser half; as a result, macroscopically in such woods two layers are distinguished in the annual ring, with a more or less distinct boundary between them: one light layer—the spring wood—and another dark one—the summer wood.

Bordered pits are arranged in two to four rows in the tracheids and have polygonal outlines with round, oval, or slit-like apertures.

Gigantoxylon tabulatus sp. nov.

Pl. IX, figs. 1–5; Pl. X, figs. 1–5

Type species. Specimen 5, collection of the TPI, Kuzbass, Leninsk District, borehole 2450, depth 692 m.

Diagnosis. Transverse section. Macroscopically, the annual rings are expressed; their width is 1.5–3 mm. The annual ring, as a rule, is subdivided into two layers: the lighter one, occupying approximately two thirds of the width of the ring, corresponds to the initial part of the annual ring, and the darker one—one third of the width of the ring—to its outer part. The boundary of the rings is rather even and distinct.

Under the microscope: the boundary of the annual rings is clear, even, or slightly wavy. The spring cells are quadrangular, their walls even or slightly sinuous, thin. Usually they are, to one degree or another,

elongated lengthwise. Sometimes the cell walls bend more strongly and the cells acquire rounded outlines. The dimensions of the spring cells are \(23.4—46.4 \times 34.8—69.6\ \mu\). Gradually the cells become shorter and acquire square outlines; the cell walls thicken somewhat; sometimes at this level the cell walls become more wavy than was observed in the early-spring cells, and the cells acquire rounded-oval outlines. Then the cells of this intermediate type rather abruptly become smaller, their walls straighten, and the cells become either square, but smaller than the preceding ones: \(11.6—34.8\ \mu\), or somewhat compressed in the radial direction. The walls of these cells are considerably thickened. Such cells constitute that darkest part of the annual ring which is distinguishable macroscopically. To the end of the annual ring the cells of this layer change almost not at all, except for the cells at the very periphery of the annual ring, where they become more flattened in the radial direction; their dimensions are \(32.5—39 \times 13—26\ \mu\).

Within the annual ring, as a rule, in the dark layer of the summer wood, areas of rather dense cells with strongly sinuous walls are observed; these areas have different widths; in places they encompass the entire width of the second, dark layer of the ring, while concentrically they are rather long, but are not sustained in the form of rings.

The medullary rays are straight, long, and usually extend through two annual rings and more. They pass straight across the boundary of the annual ring, or bend slightly; at this point there are 7–8 rays across the diameter of the microscope field of view. Where areas with strongly sinuous cells are present, the rays bend rather strongly upon entering such areas. Areas are often observed where medullary rays and rows of tracheids converge in a bundle. Two such bundles on one radius may be turned with their apices toward one another. It is possible that these areas correspond to mechanical injuries during the life of the plant.

Tangential section. The tracheids of the autumn wood are narrow, \(13—26\ \mu\) wide; their walls are even, and their ends are shortly pointed, or slightly rounded and often somewhat bent. The spring tracheids are broad, up to \(65\ \mu\); their walls are not infrequently notched, and their ends are bluntly rounded and somewhat bent. There are many medullary rays, 25–28 in the field of view of the microscope; the rays are high, uniseriate, and consist of 4–25 cells. The bulk of the rays consists of 6–15 cells. The ray cells are square or quadrangular; cell height \(23.4—34.8\ \mu\), width \(23.4—46.4\ \mu\).

Radial section. The autumn tracheids, up to \(26\ \mu\) wide, have even walls. The spring tracheids are \(58—65\ \mu\) wide, with notched walls. The ends of the tracheids are bluntly rounded, bent; sometimes they converge in a bundle, and sometimes the bent ends of opposite tracheids form a fir-tree pattern.

The medullary rays consist of long barrel-shaped cells, slightly constricted at the cross-walls; the latter are straight, rarely oblique. The height of ray cells is \(17.4—34.8\ \mu\), their length \(92.8—174\ \mu\).

The pits are bordered, small, up to \(13\ \mu\) in greatest diameter, closely approximated; their shape is rounded-polygonal; sometimes the pits are slightly elongated in width. The pits are arranged in 2–3 rows on the tracheid, depending on the width of the latter. The pit apertures are dot-like, round, possibly oval, situated transverse to or oblique relative to the tracheid. Lens-shaped formations are often encountered, consisting of a group of short tracheids, and more often broader tracheids are observed in the center of such a formation. Possibly these formations should be regarded as primordia of a conducting system, similar to the resin canals of modern coniferous plants.

On both longitudinal sections, light, rounded or polygonal inclusions of resin (?) are often encountered. These inclusions are located—

depending on tracheids, one inclusion may be situated on 2–3 tracheids, or may also occur in a single tracheid.

Comparisons. The species described is very close to the species G. impalbilis sp. nov. of the same genus. These species should be distinguished by the character of the medullary rays in tangential section: in G. tabulatus sp. nov. the rays consist of a larger number of cells, whereas in G. impalbilis the height of the rays is insignificant: 2–3 cells.

Distribution. Leninsk district, borehole 2450, depth 692 m. Kolchugino Series.

Gigantoxylon impalbilis sp. nov.

Plate XI, figs. 1–5; Plate XII, figs. 1–5

Type species. Specimen 15, collection of the Tomsk Polytechnic Institute, Kuzbass, Leninsk district, Zainskii area, borehole 2490, depth 286 m.

Transverse section. Macroscopically the annual rings are expressed; the boundaries of the rings are distinct and fairly even. Ring width 2–5 mm; each ring is subdivided into two approximately equal layers: a lighter one—spring wood—and a darker one—summer wood.

Under the microscope: the boundary of the annual rings is distinct, even or slightly wavy. The cells of the spring wood are quadrangular, more rarely rounded. The cell walls are rather thin, even, more rarely wavy. The cells are usually elongated radially, sometimes square. Cell dimensions: 29.2–65 μ—the length of the cells; 17.2–39 μ—the width of the cells. Gradually the length of the spring cells decreases, the cell wall becomes thicker, and the cells acquire square outlines. At the end of the annual ring the cells become quadrangular, flattened in the radial direction, with thick walls (up to 19 μ); the lumina of these cells not infrequently become slit-like. The dimensions of such cells are 11.6 × 23.4 μ. The square cells, as well as the flattened cells at the end of the annual ring, are denser and darker in comparison with the spring cells and account for the presence of the dark layer in the annual ring. In addition, in this part of the annual ring, much more often than in the spring wood, there occur groups of cells with strongly sinuous walls. These cells at times are extremely dense and occupy the entire second half of the annual ring, while remaining concentric over a considerable distance.

There are few medullary rays. At the boundary of an annual ring, across the diameter of the microscope field of view, from 2 to 6 rays are counted. The rays are short, usually not longer than the width of the annual ring. In the spring wood the rays are rectilinear; they pass straight through the boundary of the annual ring, or bend slightly, but where the rays enter groups of cells with sinuous walls, even if they are situated at the boundary of the ring, the rays necessarily refract or bend wave-like, and, passing through groups of cells with sinuous walls, sometimes the rays themselves become wavy. Several cells of the pith have been preserved; they are polygonal, 26.2–52.2 μ in diameter; some of them have thickened walls—sclereids (?). Farther on a strand of primary wood is visible, probably of mesarch structure, since it is not seen that the strand of primary xylem is separated from the secondary xylem by cells of the pith: it enters into the secondary wood.

Tangential section. Tracheids 11.6–46.4 μ wide, with even or, to one degree or another, notched walls and pointed ends. Sometimes the opposite ends of tracheids intertwine in a peculiar manner. Tracheids, especially narrow ones, may be wavy along their length.

Table I

Type specimen. Specimen 17, Kuzbass, Belovo District, borehole 256, depth 187 m. Kolchugino Series.

Fig. 1. Radial section. ×29.6.
Figs. 2–4. Transverse section. Fig. 2 ×15; fig. 3 ×180; fig. 4 ×72.
Fig. 5. Tangential section. ×180.

Table II

Leninskoxylon doliiformis sp. nov.

Type species. Specimen 3, Kuzbass, Leninsk district, borehole 2450, depth 10.42 m. Kolchugino Series.

Figs. 1–3. Transverse section. Fig. 1 × 15; figs. 2, 3 × 180.

Table III

Leninskoxylon doliiformis sp. nov.

Type species. Specimen 3. Kuzbass, Leninsk district, borehole 2450, depth 10, 42 m.
Kolchugino Series

Figs. 1, 4, 5. Radial section. ×180.
Fig. 2. Transverse section. ×180.
Fig. 3. Tangential section. ×180.

Table IV

Microxylon debilis sp. nov.

Type species. Specimen 18. Kuzbass. Leninsk District, borehole 2456, depth 692 m.

Figs. 1–3. Cross section. Figs. 1, 3 × 180; fig. 2 × 15.

Fig. 4. Tangential section. × 180.

Plate V

Leninskoxylon diplostichus sp. nov.

Figs. 1, 2, 4. Specimen 1. Kuzbass, Nikitino locality, borehole 2182, depth 252.7 m. Kolchugino Series.
Fig. 1. Transverse section, ×15; Fig. 2. Same, ×180; Fig. 4. Radial section, ×180.

Fig. 3. Type specimen. Specimen 18. Kuzbass, Leninsk District, borehole 2456, depth 692 m. Radial section, ×180.

Plate VI

Microxylon debilis sp. nov.

Type species. Specimen 11, Kuzbass, Leninsky district, borehole 2490, depth 109.7 m. Kolchugino Series.

Figs. 1, 2. Transverse section: fig. 1 ×29.6; fig. 2 ×180.
Figs. 3, 4. Radial section. Fig. 3 ×180; fig. 4 ×29.6.
Fig. 5. Tangential section ×180.

Table VII

Microxylon debilis sp. nov.

Fig. 1. Transverse section. ×15. Type specimen. Specimen 11. Kuzbass, Leninsky District, borehole 2490, depth 109.70 m.

Figs. 2, 3, 4. Specimen 12. Kuzbass, Leninsky District, borehole 2456, depth 283 m.
Fig. 2. Transverse section. ×180; Fig. 3. The same. ×15.
Fig. 4. Tangential section. ×180.

Table VIII

Myeloxylon heteromerus sp. nov.

Type species. Specimen 4. Kuzbass, Nikitinskoye locality, borehole 2480, depth 73 m.
Figs. 1, 2, 4. Transverse section. Fig. 1 ×15; fig. 2 ×180; fig. 4 ×29.6.
Fig. 3. Tangential section. ×180.
Fig. 5. Radial section. ×180.

Table IX

Gigantoxylon tabulatus sp. nov.

Type species. Specimen 5. Kuzbass, Leninskii District, borehole 2450, depth 692 m.
Figs. 1, 5. Transverse section. Fig. 1—×15; fig. 5—×180.
Figs. 2, 3, 4. Tangential section, ×180.

Table X

Gigantoxylon tabulatus sp. nov.

Type species. Specimen 5. Kuzbass, Leninsky District, borehole 2450, depth 692 m.
Figs. 1, 5. Transverse section. Fig. 1 ×180; Fig. 5 ×29.6.
Fig. 3. Tangential section, ×180.
Fig. 4. Radial section, ×180.

Table XI

Giganxylon impalbilis sp. nov.

Type species. Specimen 15. Kuzbass, Leninsk District, borehole 2490, depth 286 m.
Fig. 1. Cosoradial section. ×180.
Fig. 2. Transverse section. ×15.
Fig. 3. Tangential section. ×180.
Fig. 4. Radial section. ×29.6.
Fig. 5. Cosotangential section. ×180.

Plate XII

Giganxylon impalpibilis sp. nov.

Holotype. Specimen 15. Kuzbass, Leninsk District, borehole 2490, depth 286 m.

Figs. 1, 2, 3, 5. Transverse section. Fig. 1 ×29.6; figs. 2, 3, 5 ×180.
Fig. 4. Tangential section. ×29.6.

Medullary rays are few—13–28 in the field of view of the microscope, uniseriate, small, consisting of 1–6 cells. The main mass of the rays consists of 2–3 cells. Biseriate rays occur extremely rarely, and the cells of these rows are arranged alternately. The ray cells are oval, rounded, resembling links of a chain. The height of the ray cells is 17.4–23.4 μ, and their width is 11.6–17.4 μ. In the tangential section, pores located on the radial walls of the tracheids sometimes show through in the walls of the tracheids. Sometimes light, round and polygonal resin inclusions (?) are visible, arranged irregularly.

Radial section. Tracheids 12–46.4 μ wide, with pointed and sometimes interlaced ends. Tracheids that are rather short, about 500 μ, occur. Sometimes the tracheids are slightly wavy; this especially applies to narrow tracheids, whose walls are more even, whereas the walls of broad tracheids are more often slightly notched.

Bordered pits are arranged in the tracheids in 2–4 rows, depending on the width of the tracheid. The pit dimensions are up to 11.6 μ in diameter; they are rounded-polygonal and somewhat elongated in width. The pit apertures are round or oval, arranged transversely or slightly obliquely with respect to the tracheid.

The medullary rays consist of elongate barrel-shaped cells, approximately 17.4 μ high and 125.6 μ long.

Comparison. See the description of the species G. tabulatus sp. nov.

Distribution. Leninsk District, Nikitinskoe deposit, borehole 2478, depth 117 m. Zainskii area, borehole 2490, depth 286 m.

LITERATURE

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9. Zalessky M. D. Communication préliminaire sur un nouveau Dadoxylon a faisceaux de bois primaire autour de la moelle, provenant du devonien superieur du bassin du Donetz. Izvestiya Akademii nauk SSSR, series 6, No. 12, 1909.

10. Zalessky M. D. Sur un bois nouveau Metacaenoxylon carpentieri Zal. du terrain permien supérieur du bassin de Kousnetzk. Izv. Akad. nauk SSSR, Department of Mathematical and Natural Sciences, series VII, No. 5, 1935.

11. Zalessky M. D. Structure anatomique du stipe d’une nouvelle osmondée du terrain permien du bassin de Kousnetzk. Izv. Akad. nauk SSSR, Department of Mathematical and Natural Sciences, series VII, No. 5, 1935.

12. Zalessky M. D. Sur quelques végétaux fossiles nouveaux des terrains carbonifères et permiens du bassin de Donetz. Problems of Paleontology, vol. II–III, 1937.