scholarly journals X. On the organization of the fossil plants of the coal-measures. —Part IX

1878 ◽  
Vol 169 ◽  
pp. 319-364 ◽  
Keyword(s):  
Vascular Tissue ◽  
Transverse Section ◽  
Great Majority ◽  
Longitudinal Section ◽  
Variable Number ◽  
Transverse Diameter ◽  
Fossil Plants ◽  
Circular Orifice ◽  
Coal Measures ◽  
Medullary Cells

In Part I. of this series of memoirs (Phil. Trans. 1871, Plate 25, fig. 16, and Plate 27, fig. 39, p. 487) I described what appeared to be a transverse section of a Calamite, in which the woody wedges showed no traces of the longitudinal canal that occupies the innermost angle of each of these primary wedges in true Calamites. Not having at that time the materials which I have since accumulated, I was unable to say much about this exceptional specimen. I now know that it is not a Calamite, but a plant having a wholly different structure, and to which I propose assigning the provisional name of Astromyelon, from the peculiar stellate form which transverse sections of its pith exhibit. The plant had branching, unarticulated stems, a feature which at once distinguishes it from the Calamites, though transverse sections of the two plants exhibit such remarkable resemblances. It is one of the more common of the forms met with in the Oldham nodules. I have rarely seen specimens of it more than 0·25 in diameter. One example alone, represented in fig. 5, has had a diameter of nearly 0·75. Fig. 1 represents the more usual aspect of transverse sections of this plant enlarged 20 diameters. It consists of a central parenchymatous medulla, a , surrounded by an exogenous cylinder of vessels arranged in a very regular series of primary wedges, b , corresponding closely in all respects with those of Calamites, except in the absence of the long canals already referred to. The central cells of the medulla are much larger than those of the circumference, some of the former having a diameter of ·011, whilst the peripheral ones are not more than ·0041. In the longitudinal section, fig. 2, a , and fig. 3, a ', these medullary cells are seen to be somewhat elongated vertically, being often ·022 in length. The cells have usually rectangular partitions, and are arranged in vertical rows, as in many living ferns; one or two of the rows in immediate contact with the vascular zone (fig. 3, a ') have a similar arrangement, though they are much narrower in their transverse diameter. In the great majority of cases the pith is solid. In but a few instances have I found it otherwise. Two of the latter are represented in figs. 4 and 5. Fig. 5 further presents an example in which the medulla has had an unusually great diameter in proportion to that of the vascular zone. This exogenous zone is made up of a variable number of primary vascular wedges (figs. 1, b , 5, b ), each one of which is composed of numerous radiating vascular laminæ separated by medullary rays. The remarkable uniformity in their size and the regularity in the arrangement of these wedges gives to the transverse sections of the medulla the star-shaped outline already referred to. At their inner or medullary apex each of these wedges commences at a few vessels of somewhat larger size than those composing the rest of the vascular zone. These are observable in fig. 1, but they are much more conspicuous in some examples than in others. Fig. 7 represents a section, for which I am indebted to Mr. Butterworth, in which these vessels are extremely conspicuous. The medulla of this specimen is much disorganized by mineralization, but it has not been fistular. Its diameter is much less than is usually the case, contrasting strongly in this respect with fig. 5. In Mr. Binney’s monograph on the Calamites he figured, at page 20, what he believed to be part of a primary wedge of a Calamite, adding the remark, that in these Calamites “the wedge-shaped bundles of pseudo-vascular tissue originate from a small circular orifice or opening, sometimes simple, as in the specimen now under consideration, but in other instances apparently divided into several parts, as shown in the annexed woodcut (fig. 3).” I have no doubt that the latter examples were specimens of Astromyelon, which, like myself, Mr. Binney then mistook for Calamites.

scholarly journals The Bakerian lecture—On the organization of the fossil plants of the coal-measures.—Part IX. On the latest researches into the organization of the fossil plants of the British coal-measures, especially of the calamites and lepidodendra

1878 ◽  
Vol 26 (179-184) ◽  
pp. 411-415
Keyword(s):  
Transverse Section ◽  
Distinct Type ◽  
Fossil Plants ◽  
Additional Information ◽  
Solitary Cell ◽  
Coal Measures

The first plant noticed is one of which a transverse section was figured in the lecturer’s Memoir, Part I., under the belief that it was Calamitean. It now proves not to be so, but is a branching non-articulated plant, lacking the nodes and the longitudinal internodal canals so characteristic of the Calamites. It has a large parenchymatous medulla with radiating prolongations separating the very distinctly defined wedges of the vascular zone. From the peculiar shape thus given to transverse sections of the medulla the author has assigned to the plant the provisional name of Astromyelon . In the place of the canal of Calamites the thin medullary extremity of each vascular wedge is occupied by a few larger and often more conspicuous vessels than those forming the rest of the wedge. The medulla farther differs from that of Calamites in being rarely fistular. Each wedge consists of a series of regular radiating laminæ of barred vessels separated by numerous medullary rays—the latter varying in composition from a solitary cell to numerous cells arranged in single vertical series. Nearly all the stems and branches of this plant are found to be decorticated. One specimen found by Mr. Butterworth is surrounded by a very thin cortex consisting only of three or four layers of parenchymatous cells. Astromyelon forms another example of the numerous carboniferous plants whose vascular zone grew by exogenous additions, yet the exclusion of every modification of tissue, except barred vessels, from the vascular laminæ suggests Cryptogamic rathter than Gymnospermous aflinities. Astromyelon is the only distinct type of plant left undescribed in the lecturer’s previous Memoirs; but he has obtained a considerable amount of additional information respecting some of those previously examined.

scholarly journals IV. On the organisation of the fossil plants of the coal-measures.—Part XVII

1890 ◽  
Vol 181 ◽  
pp. 89-106 ◽  
Keyword(s):  
Transverse Section ◽  
Vascular Bundles ◽  
Fossil Plants ◽  
Outer Cortex ◽  
Vast Amount ◽  
Generic Term ◽  
Thin Walled ◽  
Coal Measures ◽  
Inner Cortex

In the fourth of this series of Memoirs (‘Phil. Trans.,' 1873, p. 377, et seq .) I described a remarkable plant under the name of Dictyoxylon Oldhamium ; I also gave reasons for substituting the late Mr. Gourlie ’s generic name of Lyginodendron for that of Dictyoxylon . In the same Memoir (p. 403) I referred to some petioles, to which I proposed to assign the name of Edraxylon ; but later researches demonstrated the necessity for abandoning this as a generic term and substituting for it the more comprehensive one of Rachiopteris aspera . In my Memoir, Part VI. ('Phil. Trans.,' 1874, Plate 2, p. 679, et seq .), I described this proposed Edraxylon under the name of Rachiopteris aspera . Certain similar features exhibited by the above two plants led me to remark in Memoir IV., p. 403, after showing that the Rachiopteris aspera was obviously the petiole of a Fern, “I think it far from impossible that these may prove to belong to Dictyoxylon ( Lyginodendron ) Oldhamium ; but since I have not yet succeeded in correlating them with any certainty, 1 shall add no more respecting them at present.” Since 1873 1 have accumulated a vast amount of material illustrative of the structure and relations of these two plants, and am now in a position to demonstrate that they respectively represent the stem and petiole of the same organism which proves to be a Fern. I was long under the conviction that the remarkable exogenous development of the stems of many of the Carboniferous Cryptogams, which I have so continuously demonstrated to exist, and which is now so universally recognised by Palæontologists, had no existence amongst Ferns. I have now to show that this development did exist amongst Ferns as well as amongst the arborescent Lycopods and Calamites, in which it is so conspicuous. Fig. 1 (Plate 12) is part of a transverse section of a stem or branch of Lyginodendron Oldhamium , in which a represents the medulla; b , the exogenous xylem zone; c , the place of the inner cortex, wanting in this specimen; d , one of the pairs of vascular bundles, so characteristic of the, cortex of this plant; e , the outermost cortex, composed, in transverse sections, of radiating bands of sclerenchyma, g , alternating with parenchymatous areas, f . At k, k we find two bundles of tracheids, like those at d , forming the centre of the cortical structures of a petiole of Rachiopteris aspera , i, i , which petiole is organically united to the cortex e of the Lyginodendron . The two bundles k, k are assuming the oblique relative positions seen in the similar bundles of the free petiole of R. aspera , represented in fig. 2. Other sections in my cabinet, similar to fig. 1, demonstrate the same facts, viz., that the pairs of bundles, fig. 1, d , which form so characteristic a feature of transverse sections of the middle cortex of Lyginodendrom Oldhamium , pass outwards, through the outer cortex, to become the tracheæal bundles of the petioles of the plant, and which petioles I had previously designated Rachiopteris aspera . I may state that my friend Graf Solms-Laubach, who has obtained numerous specimens of the Lyginodendron associated with others of Rachiopteris aspera from a locality on the continent, agrees with me in the conclusion at which I have arrived respecting their unity. The more perfect specimens of the Lyginodendron obtained during the last seventeen years have thrown yet further light upon those figured in 1873. In the latter, as at fig. 1, c, no traces of the middle bark were preserved; but examples from Halifax, for which I am indebted to my friends Mr. Cash and Mr. Spencer, of Halifax, have supplied what was wanting. Fig. 3 is a transverse section in which this inner cortex, c , is shown to consist of a zone of extremely delicate, thin-walled parenchymatous cells, scattered throughout which are numerous gum-canals, l . Three of these canals are represented, enlarged 250 diameters, in figs. 4 and 5, embedded in the thin-walled cells, c, c , of the cortex.

scholarly journals III. On the organisation of the fossil plants of the coal-measures.--Part XV

1889 ◽  
Vol 180 ◽  
pp. 155-168 ◽  
Keyword(s):  
Vascular Bundle ◽  
Transverse Section ◽  
Fossil Plants ◽  
Lower Carboniferous ◽  
Generic Term ◽  
Coal Measures

Some years ago M. Renault described some specimens of petioles of Ferns, which he identified with Corda’s genus Zygopteris , identical, in part, with Cotta’s genus Tubicaulis . In my memoir, Part VI., I described, from the lower Carboniferous rocks of Lancashire, two of M. Renault’s species, viz., Zygopteris Lacattii and Z. bibractensis ; but, from an unwillingness to multiply genera based only upon the ill understood fragments of imperfectly known plants, I proposed ( loc. cit ., p. 677) the provisional adoption of the neutral generic term Rachiopteris for a considerable number of these objects, which appeared to be either rhizomes or petioles of Ferns. Subsequent researches have, I think, shown the wisdom of doing so; at all events, further discoveries, which I now propose to put on record, unmistakably confirm my opinion. In the same memoir ( loc. cit ., p. 173) M. Renault described a rhizome, with petioles, the latter of which closely resembled those of Corda’s genus Anachoropteris , and to which the French palæontologist gave the name of Anachoropteris Decaisnii . But the structure of the rachis of this plant, especially of the transverse section of its vascular bundle, was wholly different from that of any plant previously observed. Having obtained a stem identical with this Anachoropteris , but without any petioles connected with it, I figured my specimen in my memoir, Part VI., Plate 58, fig. 51, where I described it as closely resembling M. Renault’s Anachoropteris Decaisnii .

scholarly journals VI. On the organisation of the fossil plants of the coal-measures. Part XI

1880 ◽  
Vol 30 (200-205) ◽  
pp. 550-554
Keyword(s):  
Vascular Cylinder ◽  
Fossil Plants ◽  
Coal Measures ◽  
Medullary Cells

M. Renault has recently published a memoir, in which he repro­duces the views of M. Brongniart respecting the relations which the Lepidodendra bear to the Sigillarise, still insisting that the former are cryptogamic Lycopods, whilst the latter are exogenous Gymnosperms. In endeavouring to establish this position, the French palæo-botanist concludes that if the exogenous Diploxyloid stems ( i. e . Sigillarianones) are but matured states of some Lepidodendra, every Sigillarian type of organisation ought to be found in a young or Lepidodendroid form, because, he contends, the type of the central organisation, once established, undergoes no further change. with advancing age. In support of his position, he affirms that there are three such Sigillarian types, viz., Sigillaria vascularis; 2. Diploxyloid stems ; 3. Favularia and Leiodermaria. At present he contends that only the second of these forms has been discovered in Lepidodendron Harcourtii. He further believes that there are three types of Lepidodendron known, repre­sented by—1. L. Rhodumense, with a solid central vascular axis, in which the vessels are not intermingled with medullary cells ; 2. by L. Harcourtii, in which the vascular axis is a cylinder surrounding a cellular medulla; and, 3. An undescribed plant, which he names L. Jutieri, in which the vascular cylinder is broken up into detached bundles of vessels.

VII. On the organization of the fossil plants of the coal-measures.―Part VIII. Ferns (continued) and gymnospermous stems and seeds

1877 ◽  
Vol 167 ◽  
pp. 213-270 ◽  
Keyword(s):  
Transverse Section ◽  
External Surface ◽  
Cortical Layer ◽  
Maximum Diameter ◽  
Vascular Cylinder ◽  
Fossil Plants ◽  
Vascular Elements ◽  
The Rich ◽  
The Difference ◽  
Coal Measures

In one of his valuable Memoirs on the Fossil Plants of the Carboniferous deposits of France M. Renault has described the stems of two fossil Ferns, to both of which examples characteristic petioles are attached. In these stems the chief vascular or pseudo-vascular elements are not scattered over the transverse section of the stem in detached bundles, as is usual amongst living Ferns, but they are gathered together so as to form an axial cylinder, enclosing an irregular, central, radiating medulla composed of parenchymatous tissue. In the sixth of this series of memoirs I figured (plate 58. fig. 51) a transverse section of a similar vascular axis, but without either petioles or even any investing cortical layer attached to it. In one of M. Renault’s examples the petioles associated with the stem were identical with those to which Corda gave the name of Zygopteris . In the second species, to which M. Renault assigned Corda’s generic name of Anachoropteris , the transverse section of the petiolar vascular bundle resembles that of Osmunda and Todea , as M. Renault has correctly indicated ( loc. cit . p. 176). He also points out the difference existing between the closed vascular cylinders of the stems of these two Ferns and the corresponding bundles of most living types, but thinks that something similar to them may be found amongst the Ophioglossums . I am indebted to my indefatigable auxiliary, Mr. J. Butterworth, for an interesting stem of the same type which he obtained from the rich reservoir of fossil plants near Oldham. The specimen was about 1 1/2 inch in length, whilst its somewhat oval, trans­verse section had a maximum diameter of about an inch. The external surface was strongly marked by an irregular series of transverse ridges and furrows, represented in fig. 1, and which may some day contribute to the identification of the fronds with which this stem should be associated. There aye about twenty-four of these ridges, with corresponding intermediate furrows, to each vertical inch of the stem. On making a transverse section of the specimen I found a central vascular cylinder closely resembling that seen in M. Renault’s specimen of Zygopteris Brongniarti ( l. c . pl. 3. fig. 1, a ), along with two or three secondary ones, of varying dimensions, dispersed over the area of the section. Utterly unable to interpret the relations of these several structures, I adopted the plan which proved so successful in the case of Heterangium Grievii (Phil. Trans. 1873, pl. xxx. figs. 37-44), and had about an inch of the specimen cut up into the series of closely consecutive, transverse sections represented in figs. 2-12. By this process a partial interpretation of these sections, at least, has become sufficiently easy.

II. On the organization of the fossil plants of the coal-measures.—Part IV. dictyoxylon , lyginodendron , and heterangium

1873 ◽  
Vol 21 (139-147) ◽  
pp. 86-90
Keyword(s):  
Vascular Tissue ◽  
Fossil Plants ◽  
Coal Measures

In 1866 Mr. Binney gave the name of Dadoxylon Oldhamium to a fossil stem of a plant from the Lower Coal-measures of Lancashire, believing it to belong to the same class of Grymnospermous Exogens as the Pinites of Witham and the Dadoxylon of Endlicher. In 1869 the author pointed out that the reticulated markings upon the surface of its vessels were modifications of the spiral fibre of fibro-vascular tissue, and not the disks of what is often designated glandular fibre. He consequently separated the plant from the Dadoxylons under the name of Dictyoxylon Oldhamium .

scholarly journals IV. On the organization of the fossil plants of the coal-measures.—Part II. Lepidodendra and Sigillariæ

1871 ◽  
Vol 19 (123-129) ◽  
pp. 500-504
Keyword(s):  
Linear Order ◽  
Transverse Section ◽  
Vascular Bundles ◽  
Early Type ◽  
Fossil Plants ◽  
Special Linear ◽  
Standard Of Comparison ◽  
Coal Measures

The Lepidodendron selaginoides described by Mr. Binney, and still more recently by M r. Carruthers, is taken as the standard of comparison for numerous other forms. It consists of a central medullary axis composed of a combination of transversely barred vessels with similarly barred cells; the vessels are arranged without any special linear order. This tissue is closely surrounded by a second and narrower ring, also of barred vessels, but of smaller size, and arranged in vertical laminae which radiate from within outwards. These laminae are separated by short vertical piles of cells, believed to be medullary rays. In the transverse section the intersected mouths of the vessels form radiating lines, and the whole structure is regarded as an early type of an exogenous cylinder; it is from this cylinder alone that the vascular bundles going to the leaves are given off.

scholarly journals III. On the organization of the fossil plants of the coal-measures.—Part V. Asterophyllites

1874 ◽  
Vol 164 ◽  
pp. 41-81 ◽  
Keyword(s):  
Transverse Section ◽  
Careful Study ◽  
Parent Plant ◽  
Fossil Plants ◽  
General Aspect ◽  
The Third ◽  
Gradual Development ◽  
Established Fact ◽  
Coal Measures ◽  
Time Aware

In 1871 I published, in the 5th volume of the third series of the 'Memoirs of the Literary and Philosophical Society of Manchester,’ a description of a new Cryptogamic fruit, to which I gave the provisional name of Volkmannia Dawsoni . One of the most remarkable features of this curious organism was seen in a transverse section of its central vascular axis, which appeared to be a triangular structure with truncated angles. When the above memoir was read (February 7, 1871) I had seen no stem having a similar structure; but after a careful study of the fruit, I said, “The verticillate arrangement of its bractigerous disks and bracts suggests the probability that we must seek for the parent plant amongst such as have their foliage arranged in corresponding verticils; and if this law of association be a sound one, we are apparently shut up to the three genera, Asterophyllites , Annularia , and Sphenophyllum ”. After reviewing the various features of these plants, I arrived at the conclusion that “it is the fruit either of Asterophyllites or of Sphenophyllum ; and, judging from the general aspect of its bractigerous disks, I am more disposed to identify it with the former than with the latter”. I was not at that time aware that Professor Renault, of Cluny, had found a stem at Autun having a similar triangular axis, and which he also had referred to Sphenophyllum (‘Comptes Rendus,’ 1870). My attention was at once directed to the discovery of true stems having a similar structure, and I soon found a few examples in the cabinets of Messrs. Butterworth and Whittaker of Oldham. But these gave me no such evidence as I required respecting the nature of the foliage with which these stems had been clothed, neither did any of them afford proof even that the plant had been a jointed one. I then turned to the coal-seam from which the fossil strobilus was obtained, and was at length rewarded by the discovery of a cluster of stems, each one of which was clothed with its peculiar bark, having the enlarged lenticular nodes exquisitely preserved, and the verticils of Asterophyllite-leaves radiating from the thin margin of each nodal disk in precisely the same way as the bracts had done from the corresponding portions of the fruit already described. What had previously been an inferred probability thus became an established fact; hence I have now no hesitation whatever in referring both the above fruit and the stems which I am about to describe to the genus Asterophyllites . Amongst the other specimens sent to me from Burntisland by G. Grieve, Esq., were some stems having a similar structure, but of larger size than any I had met with in Lancashire; but, though exquisitely preserved, the fragments were internodal ones, and not sufficiently long to exhibit the structure of the nodes. I shall adopt in this memoir the plan which I followed in the third of this series of monographs, in which I treated of the Burntisland Lepidodendroid plants; I shall com­mence with the youngest twig of the Lancashire type which I have met with, and then trace the gradual development of the organism through the addition of successive exogenous growths by which the twig was thickened and finally converted into branch and stem.

XIV. On the organization of the fossil plants of the coal-measures.—Part X. Including an examination of the supposed radiolarians of the carboniferous rocks

1880 ◽  
Vol 171 ◽  
pp. 493-539 ◽  
Keyword(s):  
Volcanic Ash ◽  
Entire Group ◽  
Limited Area ◽  
Fossil Plants ◽  
Outer Bark ◽  
Very Old ◽  
Charles Lyell ◽  
Thin Cylinder ◽  
Large Tree ◽  
Coal Measures

In 1865 my friend Mr. Edward Wunsch, of Glasgow, made the discovery of some thin carboniferous shales imbedded in volcanic ash at Laggan Bay, in Arran. These beds have already been described by their discoverer, and their fossil contents referred to by Mr. Binney, Mr. Carruthers, and Sir Charles Lyell. From within a very limited area the bases of more than 13 large erect stems of carboniferous trees have been extracted by Mr. Wunsch, the most important of which he has kindly placed in my hands. In the summer of 1877 we conjointly superintended some quarrymen, who tore up large portions of these strata with the result, I believe, of obtaining a fair knowledge of the nature of these beds and their contents. The trees certainly stood where they originally grew; most of them consisted of a thin cylinder of the outer bark, which was deeply fissured longitudinally but exhibited no true Sigillarian flutings or traces of leaf-scars. The interior was in most cases filled with volcanic ash, but in a few instances by vegetable débris introduced from without; and in one specimen, imbedded in the vegetable mass, are several decorticated Diploxyloid vascular axes of very old stems. These have been referred to as young growths that sprang up within the bark-cylinder; but such is not the case. Each one is not only decorticated, but is large enough to be the vascular axis of the large tree within which the entire group occurs, and where they are mixed up with fragments of the similar vascular axes of Stigmaria and other plants.

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