6 Johnstone, Calamiies {Calamitina) varians, Sternb. 



The average measurements are : — 



Longitudinal 6mm.s. )• , ,. 



° vin lower line. 



Horizontal 8 ,, ) 



' " [in upper line. 



Longitudinal 7 



Horizontal n 



They therefore cover about half of the internode in 

 which they emerge, whilst at the same time encroaching 

 on that below. 



The general appearance of a scar is that of a deep 

 cavity, the centre of which lies much closer to the lower 

 edge, the upper slope long and gentle, the lower short and 

 abrupt. Within these broader outlines more minute details 

 can be made out. In the best examples a definite area 

 P^ {Plate) is clearly separated from the remainder as the 

 deepest region — its outline is nearly circular ; it is steeply 

 funnel-shaped ; its edge is sharply cut off from the upper 

 slope of the stem xylem and may be an upstanding ring. 

 From this pit the slope is gradual to the top rim, which is 

 narrow-edged and simple, projecting sharply and sloping 

 away again into the surface of the short internode : there 

 are no complications on this upper edge. It must be 

 noted that the medullary ray markings of the internode 

 curve over the rim, and are continued to the edge of/" ; 

 they look exactly as if the branch had been resting against 

 them and preventing their outward development. This 

 feature is absent from the lower slope. 



The lower edge of the scar is less simply outlined. 

 One particularly well-preserved example shows what may 

 be described as a secondary ridge — very narrow — on the 

 lower rim, with a narrow trench on either side of it ; this 

 is also seen, but less distinctly, on other scars. The lower 



of the trenches is part of a wavy depression, s s, 



which runs, with accidental breaks, under the whole row ; 

 it may be the counterpart of that which is overhung by 



