Mu d s cda uM A c ecd 
WEN S 
NOTES ON CALAMOPITYS. 207 
secondary tracheides radiating out from it, and starting from its flanks as 
well as from the abaxial side. The protoxylem is disorganized but its 
position is evident (Phot. 2); it lies deep in the interior of the xylem- 
strand, nearer the outer than the inner edge. It will be noticed that the 
elements lying on the inner side of the protoxylem are decidedly larger than 
those towards the exterior. On the inner side the xylem-strand is not sharply 
delimited, for the pith was *mixed," and also there was some connection with 
a reparatory strand, better shown in a later section. 
The next section shows little change. In section 3 (Phot. 3) the outward 
progress is still very slight. The protoxylem of the outgoing strand appears 
to have divided into two, so far as the imperfect preservation of this part 
permits one to judge (Phot. 4). The most interesting point in this section, 
however, is that the connection of the leaf-trace with a strand remaining in 
the stele is clearly shown. This strand lies on the inner side of the xylem of 
the trace and somewhat to one side (Phot. 4). Its protoxylem is evident 
(though a wide crack passes through it). The two strands are clearly in the 
act of separating. The structure is almost identical with that shown, from 
another specimen, in Pl. 35. fig. 4 of the Kentucky paper (Scott & Jeffrey, 
1914). The new evidence completely confirms the interpretation there 
suggested, that the division in question “separated the trace as a whole from 
a reparatory strand which did not immediately pass out” (p. 325). 
Two sections higher up (Phot. 5) the connection between the reparatory 
strand and the leaf-trace is almost severed. Though the xylem-strand of 
the trace is damaged, the two distinct protoxylem-groups are now evident, 
and there are signs of a division of the centripetal portion of the xylem. 
In the following four sections the outward movement of the leaf-trace is 
very slow, but the gradual division of the xylem into two becomes more 
marked (see Phot. 6, from the 9th section). So far, however, it is only the 
inner part of the strand that is affected, while the outer, centrifugal, portion 
is still continuous. Even in the former, the separation appears wider than 
it actually was, owing to decay of some of the elements. 
In the succeeding sections the fan of secondary wood corresponding to the 
trace broadens out, the lateral rows making a wider curve. At the same 
time the primary xylem is completing its division. In Phot. 7, from 
section 13, the two distinct strands are evident, though perhaps still slightly 
connected on the abaxial side. The radial series of the secondary wood here 
begin to show an arrangement corresponding to the doubling of the primary 
strand, the original fan tending to resolve itself into two fans, as shown by 
the slight opposite curvature of the adjacent median rows (Phot. 7). 
The two strands of the leaf-trace now rapidly separate, and the outward 
movement also becomes more marked. In the 15th section (Phot. 8) the 
strands are separated by more than their own width and their protoxylem 
centres are about 2:5 mm. apart. At this level a median band of secondary 
82 
