scholarly journals ON THE STRUCTURE AND AFFINITIES OF FOSSIL PLANTS FROM THE PALAEOZOIC ROCKS.—V. ON A NEW TYPE OF SPHENOPHYLLA-CEOUS CONE (SPHENOPHYLLUM FERTILE) FROM THE LOWER COAL-MEASURES

1905 ◽  
Vol os-19 (1) ◽  
pp. 168-169
Author(s):  
D. H. SCOTT
Keyword(s):  
New Type ◽  
1905 ◽  
Vol 74 (497-506) ◽  
pp. 314-315
Author(s):  
Dukinfield Henry Scott

The class Sphenophyllales, of which the fossil described is a new representative, shows on the one hand clear affinities with the Equisetales, while on the other it approaches the Lycopods; some botanists have endeavoured to trace a relation to the Ferns. The nearest allies among recent plants are probably the Psilotaceæ, which some writers have even proposed to include in the Sphenophyllales.


One of the most striking results of palæobotanical research has been the discovery that in Palæozoic times a class of Vascular Cryptogams existed, quite distinct from any of the three main groups of Pteridophyta with which we are familiar in the recent flora. This class, the Sphenophyllales, while showing in certain respects a clear affinity with the Equisetales, in other characters rather approaches the Lycopods, and some botanists have endeavoured to trace a relation to the Ferns. The work of the last few years has pointed to a connection between this extinct group and the recent Psilotacese; some authors have gone so far as to include the latter in the Sphenophyllales. So far as fossil members are concerned, the class is represented by two genera only—the extensive and comparatively well-known genus Sphenophyllum , ranging from Devonian to Permian, or, perhaps, Triassic times, and the more recently discovered Cheirostrobus from the Lower Carboniferous, of which only the fructification is at present known. Each of these genera must be regarded as representing a distinct family within the class. Spheuophyllum , indeed, is a “genus” only in name, embracing, if we judge by the fructification, several types of generic value. The object of the present communication is to describe a newly discovered fossil strobilus, clearly belonging to the family Sphenophylleæ, but presenting new features of considerable importance.


1880 ◽  
Vol 171 ◽  
pp. 493-539 ◽  

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.


1889 ◽  
Vol 45 (273-279) ◽  
pp. 438-440

In this memoir the author first calls attention to detached observa­tions made in his earlier memoirs relating to the manner in which a medullary axis is developed in the interior of each of the primary vascular bundles of the Carboniferous Lycopodiacæ.


1889 ◽  
Vol 180 ◽  
pp. 195-214 ◽  

During the last twenty years many single examples of vegetable forms from Carboniferous rocks have come into my possession, which were obviously different from any hitherto described. But I have carefully abstained from publishing such specimens until examples of each multiplied in my cabinet, enabling me to determine how far their apparently distinctive features were constant, and not merely individual, variations. Many such imperfectly known forms still occupy a drawer in my cabinet; but in the present Memoir I propose to describe several of which examples have accumulated so far as to enable me to speak with reasonable certainty as to their specific distinctiveness. In several of my previous memoirs I have from time to time called attention to a curious development of a medulla in the centre of the axial vascular bundle, especially of the Lepidodendra. This was especially done in the Memoir, Part III., when describing the Burntisland Lepidodendron , to which, as was also the case with the Arran form (Part X.), I have not yet ventured to give a specific name.


The existence or non-existence of the remains of Palms in the Carboniferous strata has long been a debated geological question. Accepting the determinations of Corda as announced in his ‘Flora der Vorwelt,’ many geologists admitted these true endogens into their lists of Carboniferous plants. Cotta had figured, in his ‘Dendrolithen,’ three very anomalous stems, under the names of Medullosa porosa , Stellata , and elegans . Corda, in his 'Flora der Vorwelt,’ subsequently figured two stems from Carboniferous strata obviously allied to one, at least, of Cotta’s types, under the names of Palmacites carbonigerus and P. leptoxylon , which he placed in the class of Palms. Cotta’s figures of Medullosa elegans are very misleading, though they are not very unlike the specimens which he probably described. Some specimens now in the British Museum which came direct from Cotta, and for having my attention drawn to which I am indebted to my friend Mr. Carruthers, exhibit a remarkable areolation when cut transversely. This areolation Cotta has not only copied but exaggerated; hence the peculiar aspects of his figures 1 & 8 of his Medullosa elegans ; it certainly is not a constant and normal feature, but the result of some change produced subsequent to the life of the plant—most probably a consequence of partial desiccation of the stem. Cotta’s drawings of the cortical layer also are very misleading; hence it is very unsafe to accept his delineations apart from the study of his specimens, some of which, I fear, are no longer to be found. The consequence is that two of his species, M. stellata and M. porosa , remain too obscure to be relied upon without further evidence than Cotta has handed down to us. The first to throw doubt upon the Monocotyledonous character of these plants was M. Brongniart in his ‘Tableau des genres de Végétaux fossiles,’ published in 1849, extracted from the ‘Dictionnaire Universel d’Histoire Naturelle.’ He identified Cotta’s Medullosa elegans with some important plants not uncommon in the Carboniferous beds of Autun; and whilst he thought that these specimens displayed a structure analogous to that of some Monocotyledons, especially of Draœena, he adds, “il y ait des différences fort essentielles et qui rendent très-difficile d’établir des rapports entre ces fossiles et les végétaux vivants”*. M. Brongniart consequently proposed to make Cotta’s Medullosa elgans the type of a distinct genus under the name of At a later page of his work (p. 97) he further gives a list of fourteen Carboniferous Monocotyledons, in which he includes seven species of Trigonocarpum , his proposed genus Myeloxylon , and the Palmacites carbonigerus and leptoxylon of Corda, at the same time declaring that all these supposed Carboniferous Monocotyledons are “ très-douteuses et imparfaitement connues.” At p. 89 of his work he retains Corda’s genus Palmacites , but remarks respecting the two species from the Carboniferous strata, viz. P. carbonigerus and leptoxylon , that they appear to be distinct from the Palms, and probably also from the group of Monocotyledons, thinking them analogous to the Medullosa elegans of Cotta, adding, in reference to the latter plant, “ qui n’est certainement pas un palmier.”


1873 ◽  
Vol 21 (139-147) ◽  
pp. 394-398 ◽  

On two occasions the author directed attention, in the Proceedings of the Royal Society (vol. xx. pp. 95 & 435), to the structure of some stems which appeared to him to belong to the well-known genus Asterophyllites , briefly pointing out at the same time their apparent relations to a strobilus of which he had previously published figures and description (Transactions of the Literary and Philosophical Society of Manchester, third series, vol. v. 1871) under the name of Volkmannia Dawsoni . In the present memoir he gives a detailed exposition of the various parts of the plant, including the roots, rootlets, stems, branches, leaves, and fruit, in different stages of their development. This is done chiefly in two modifications of the primary type—one from the Lower Coal-measures Oldham in Lancashire, the other from those of Burntisland.


The fossils which form the subject of the present paper are Cryptogamic strobili showing evident Lycopodiaceous affinities, but differing in important points from other fructifications of that family, so that it appears necessary to establish a new genus for their reception. The specimens are derived from the Coal-measures of Lancashire and Yorkshire, and are calcified, the internal structure being thus preserved in considerable perfection. As our present knowledge of the forms in question is entirely due to the researches of the late Professor W. C. Williamson, it will be necessary to give a short historical summary of the results which he attained, before going on to my own observations.


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