32 PROF. W. C. WILLIAMSON ON THE 



an inch from the inner surface of the prosenchymatous 

 cylinder, in an undivided manner ; but its tendency to 

 break up into subdivisions is seen in the crenulated out- 

 line e, in the sections figs. 3 and 4. This crenulation is 

 the result of deep radiating grooves indenting the inferior 

 surface of the disk. These deepen as they proceed out- 

 wards, and soon divide the disk into a verticil of separated 

 bracts. In fig. 4 we see the first result of this division in 

 the series of irregular masses (//) ; but the true form of 

 these divisions is masked in the part referred to, because 

 the section has passed through them very obliquely, 

 in fact almost in the plane of their two surfaces. The 

 form and appearance of true sections are better seen at /' 

 in the same figure. But their relative positions will be 

 still better understood by referring to fig. 6, which repre- 

 sents a tangential section made vertically through three of 

 the bractigerous disks, a little externally to the point at 

 which that structure is divided into its peripheral fringe 

 of elongated bracts. Sections of these bracts are seen at 

 /', whilst at the side of the cone, /", these bracts extend 

 upwards to their termination in the plane of the section. 

 In the latter portions we see that their two epidermal 

 surfaces appear to have been more dense and solid than 

 their central portions. On turning to tranverse sections 

 of these uppermost portions of the bracts, as we see them 

 a ^ /" /" in figures 3 and 4, we discover that they here 

 become more depressed, thinner, and more leaf-like than 

 they are at/'. At the latter point they are separated from 

 each other by distinct intervals, and even at their ex- 

 tremities they have not approached sufficiently entirely to 

 hide the sporangia from view. At their bases these bracts 

 have a breadth of from '035 to '04 of an inch. 



The vertical sections, figs. 1 and 2, show the thick and 

 succulent character of the disk, and the gradual thinning 

 of the bracteated subdivisions /. The appearance of 



