436 Prof. W. C. Williamson's Further Researches [June 20, 



note at the foot of page 488. I have now got numerous examples of this 

 plant, and it proves, as I surmised, to belong to a distinct type. It has a 

 branching stem, not jointed, and having a remarkable pith. Since the latter 

 organ, when divided transversely, gives a star-shaped section, closely re- 

 sembling that of a Calamite, except that it has not been fistular, I pro- 

 pose to give to the plant the generic name of Astromyelon. I have further 

 examined a series of curious stems which I described briefly at the Edin- 

 burgh Meeting of the British Association under the name of Dictyoxylon 

 radicans ; this plant I also find must be placed in a new genus. It is 

 characterized by possessing an exogenous, woody, branching stem, com- 

 posed of reticulated vessels. It has no pith, and its bark consists of 

 cells arranged in columns perpendicular to its surface. I think it not 

 improbable that this has been the subterranean axis of some other plant, 

 since I have succeeded in tracing its ultimate subdivisions into rootlets. I 

 propose for the present to recognize it by the generic name of Amyelon. My 

 specimens of this plant are very numerous, some of them having been 

 kindly supplied to me by Messrs. Butterworth and Whittaker, of Oldham. 

 They may prove to be rhizomes and roots of the Asterophyllite described in 

 my last letter to you. 



Of this last genus I have just got an additional number of exquisite 

 examples, showing not only the nodes but verticils of the linear leaves so 

 characteristic of the plant. These specimens place the correctness of my 

 previous inference beyond all possibility of doubt, and finally settle the 

 point that Asterophyllites is not the branch and foliage of a Calamite, but 

 an altogether distinct type of vegetation having an internal organization 

 peculiarly its own. This organization is identical in every essential point 

 with that of my Volkmannia Dawsoni already referred to in my previous 

 letter, and which I do not now hesitate to designate Asterophyllites 

 Dawsoni. The peculiar triquetrous form of the young vascular axis of 

 this genus is too remarkable and too distinct from that of all other Carbo- 

 niferous types to be mistaken for any of them, and especially for that of 

 Calamites, with which it has not one single feature of real affinity. 



I have also obtained, partly through the assistance of Messrs. Butter- 

 worth and Whittaker, but especially the latter, an instructive series of 

 specimens of the genus Zygopteris, which has recently been made the sub- 

 ject of an important memoir by M. B. Renault, published in tome xii. of 

 the 'Annales des Sciences Naturelles/ Our Lancashire specimens are of 

 the type which he describes under the name of Z. Lacattii. The French 

 savant has found these plants, in one instance, connected as petioles to a 

 rhizome, which he believes to be that of a fern. Our specimens supply 

 some information additional to that published by M. Renault ; they appear 

 to me to sustain his idea that they are petioles, and I have traced in them 

 the origin of the two vascular bundles which he refers to as pores existing 

 in the bark. 1 find much reason for concluding that they are, as he sur- 

 mises, the vessels going to the secondary rachis of the pinnules. Our 



