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

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Abstract
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.

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