THE CARBONIFEROUS ROCKS OF CANONBIE, DUMFRIESSHIRE, ETC. 763 



portion directed upwards, long and acicular. Leaf cushions on the young stems 

 arranged in distinctly spiral columns ; on the old stems the leaf cushions form distinct 

 vertical rows. Leaf cushions with longitudinal keel, generally with a rhomboidal half- 

 moon-shaped scar placed above the middle, and below the scar on each side occurs a 

 somewhat bent little linear scar. Leaf cushions on the young stems generally touching 

 each other, rhomboidal, almost quadrate to elongate rhomboidal, or even obovate, and 

 with pointed or elongated ends. Leaf cushions in old age six-angled, fusiform to 

 almost lyre-shaped, generally arranged in vertical rows, and with the extremities united 

 to each other, seldom separate ; the leaf cushions on neighbouring columns alternate with 

 each other, and are separated by a more or less broad band of longitudinally wrinkled 

 or reticulated bark." 



Remarks. — The above description is that drawn up by Schmalhausen after a careful 

 examination of numerous specimens, and may be regarded as a reply to the opinion 

 expressed by Stur that Lepidodendron Glincanum belonged partly to Lepidodendron 

 Veltheimii, Sternb., and partly to Lepidodendron Volkmannianum, Sternb. # 



In addition to a large amount of material from different localities, Schmalhausen re- 

 examined the specimens seen by Stur, and several of these are figured in his PJlanzen- 

 reste der Steinkohlenformation am Ostlichen Abhange des Ural Gebirges." 



Certain forms oiLep. Glincanum have some resemblance to Lepidodendron Veltheimii, 

 and others with vertical rows of leaf cushions remind one of Lepidodendron Volkman- 

 nianum, especially the figure of a somewhat imperfectly preserved specimen given by 

 Eichwald on his pi. va. fig. 7 ; but notwithstanding this resemblance of certain 

 specimens to these two species, it does not appear possible to refer Lepidodendron 

 Glincanum to either Lepidodendron Veltheimii or Lepidodendron Volkmannianum, as 

 proposed by Stur. Even if Lepidodendron Glincanum, as refigured and described by 

 Schmalhausen, contains more than one species, it is not to either of these species that it 

 can be referred, and it may well be that Lepidodendron Glincanum, as believed by 

 Schmalhausen, may be a single but very variable species. 



The most peculiar character connected with Lepidodendron Glincanum appears to 

 be the two series into which the specimens can be divided, namely, those with spirally 

 placed leaf cushions and those on which the leaf cushions are placed vertically, the 

 latter condition being usually restricted to aged stems ; still, Schmalhausen states that 

 all these varieties are connected by intermediate forms. 



Schmalhausen recognised the following varieties : — 



a. tessellatum, pi. iii. figs. 1-4, 6. 



b. obovatum, pi. iii. figs. 7, 7a, 8. 



c. rimosum, pi. iii. figs. 9-15. 



b. sigillariiforme, pi. iii. figs. 16-19, pi. iv. figs. l-4.t 



* Ein Beitrag. zur Kenntniss d. Culm und Carbon Flora in Russland, — Verhandl. d. k. k. Geol. Reichsanstalt, vol. 

 xxviii., Jahrgang 1878, No. 11, p. 219. 



t These references apply to Schmalhausbn's paper already referred to. 



