Manchester Memoirs, Vol. li. (1907), No. IS. 11 



(8) The leaf base.. 



The leaf scar is situated at the apex of a cushion. 

 This cushion has the form of a truncated rhombic 

 pyramid about 2 mm. — 3 mm. vertically, 3 mm. horizon- 

 tally, and projecting about 1 mm. above the surface of 

 the stem. The leaf scar is only slightly less wide than 

 the base of the cushion, but is considerably shorter. The 

 vascular bundle enters the leaf base almost horizontally, 

 and in the lowest \ of its height, it passes straight to 

 the leaf scar. 



The bundle is a collateral one, the xylem being very 

 small in amount, but reinforced by the transfusion tissue. 



This transfusion tissue, composed of short tracheids, 

 either scalariform or reticulate, forms a sheath round 

 the bundle, only interrupted where the dark secretory 

 elements below the phloem occur. 



The ligular pit is very long and narrow, the ligule 

 being inserted considerably before the leaf bases become 

 separated from one another. {Fig. 4, Plate II.) 



The ligular pit opens just above the leaf scar on the 

 upper surface of the cushion. 



The ligule is not well preserved, but seems to have 

 been of the ordinary lepidodendroid type, consisting of 

 uniform small-celled parenchyma. 



The base of the ligule received an abundant supply of 

 transfusion tracheids, which bridge over the short distance 

 between theligule and thevascular bundle. {Fig. 5, Plate II.) 



The parichnos enters the tissue external to the 

 secondary cortex as a single strand of parenchyma, 

 immediately below the vascular bundle. {Figs. 8, Plate 

 III, and 4, Plate II.) 



At about the level at which the leaf bases become free 

 this strand divides into two, which rise until they cut the leaf 

 scar on each side of the vascular print, but at a lower level. 



