764 MR ROBERT KIDSTON ON THE FOSSIL PLANTS OF 



All the specimens met with at Canonbie belong to those with spirally placed leaf 

 cushions, with the exception of that given on Plate V. fig. 4 1 , where the cushions form 

 almost upright columns. 



Description of Specimens : — 



At PI. II. fig. 21 are shown fragments of small branches. A portion of one of these 

 is given enlarged two times at PL IV. fig. 37, and an outline of one of the cushions and 

 leaf scar at fig. 38. 



The leaf cushions are contiguous, rhomboidal, keeled, with lateral angles rounded ; 

 the leaf scar, which is placed above the centre of the cushion, is transversely rhomboidal, 

 lateral angles pointed, upper and lower angles rounded but prominent. This corre- 

 sponds to Schmalhausen's var. tessellata, pi. iii. figs. 1-3, but the leaf scar on my 

 specimens is a little larger. 



PL II. fig. 20, of which a portion is enlarged two times on PL IV. fig. 39, and outline 

 of the cushion and scar given at fig. 40. 



The leaf cushions here are more fusiform, slightly separated, and provided with pro- 

 longed ends, which generally unite with the prolonged point of the cushions above and 

 below in the same series, but sometimes the prolongations of the cushions do not unite, 

 but the extremities pass each other laterally. This form corresponds to Schmalhausen's 

 var. obovatum, pi. iii. fig. 7. The leaf scar, which is placed above the centre, is also 

 slightly larger than in the figures given by Schmalhausen, but I believe this may be 

 accounted for by the better preservation of my specimens. The cortex between the 

 cushions is feebly striated longitudinally. 



Plate V. fig. 41, a portion of which is enlarged two times on PL V. fig. 42, and outline 

 sketch of cushion and scar shown at fig. 43. 



The cushions here are fusiform, with long slightly bent produced extremities, with 

 a distinct tendency to form vertical columns. The produced points sometimes unite 

 with neighbouring leaf cushions, sometimes pass each other at their extremities. The 

 leaf scars are separated by a band of irregularly longitudinally striated cortex. This is 

 the var. rimosum, and corresponds to the figure given by Schmalhausen on his pi. iii. 

 fig. 12. This variety differs from Lepidodendron rimosum, Sternb., in the leaf scar being 

 proportionally larger ; it here occupies almost the complete width of the cushion, 

 whereas in Lepidodendron rimosum, Sternb., it occupies less than half the width of the 

 cushion. Lepidodendron Glincanum, var. rimosum, also differs in the coarser striation 

 of the interfoliar cortex, which is apparently not ornamented with fine oblique striae as 

 in Lepidodendron rimosum, Sternb. 



PL III. fig. 28. This specimen probably shows an older condition of the var. 

 tessellatum, with quadrate leaf cushions. The leaf scars are effaced, and the specimen 

 seems to have suffered from pressure. 



PL III. fig. 27. This illustrates a still older conditition of the plant. Only the leaf 

 cushions are shown, the leaf scar being quite obliterated, probably the result of age. 

 The specimen shows very clearly the truncation of the leaf cushions, especially at their 



