ROOTS. 7 



at its base, from e to fin Fig. 5, is slightly less than 4 inches, and that of c, from e 

 to g, exactly 4 inches. 



Fig. 6 represents the under surface of Fig. 5, in which the crucial ridges seen 

 in Fig. 4 are replaced by deep grooves. The line e of Fig. 4 is now represented 

 by a fossa, 2| inches below the level of a line drawn from c to c . Fig. 6, a, 

 represents six of the rootlet-scars, of their natural size, as seen at the base, a, of 

 the root, Fig. 5, d; and 6, b, is a copy of a similar cluster from near Fig. 5, x, of 

 the same root. These two figures show how the Stigmarian rootlets accommodated 

 themselves to the increased growth of the root, not by any additions to their 

 numbers, but by a molecular growth of the bark which pushed the rootlets further 

 apart, this separation being accompanied by a corresponding increase in the 

 diameter of each individual rootlet. 



Xtlograpb 1. 



J^ 



The Xylograph 1 represents the outlines of the underside of a fine Stig- 

 marian base of Sigillaria reniformis obtained by Mr. George Wild from the roof of 

 the Bardsley Colliery, near Ashton-under-Lyne. In this specimen, which is of 

 large size, the four primary roots become separated so near to the base of 

 the stem that their division into four can only be made out by careful 

 examination. Xylograph 2 is an outline of another specimen from the roof of a 

 coal-mine at Honeywell Lane, also in the neighbourhood of Mr. Wild's colliery. I 



