1908] DORET Y—CERATOZAMIA 209 
apical point of the scale leaves. At irregular intervals along the 
petiole are other, even smaller points. The first leaves are opposite, 
but the later ones assume the spiral phyllotaxy represented in fig. 12. 
ANATOMY 
As was above noted, the edges of the cotyledon close in after the 
exit of the plumule, the two halves of the adaxial face meeting in a 
plane represented by the line ad in jig. 13. Three bundles enter 
the cotyledon from the vascular plate, and each dichotomizes again 
and again (jig. 16), the median one being no more a “double” bundle 
than any of the others. The number of traces may be increased 
to fifteen toward the upper portion, but is gradually reduced again 
toward the tip, some bundles approximating in pairs, others dying 
out. Those in the lobes disappear lower down than the others 
(fg. 15). The bundles are collateral throughout the cotyledon, and 
their orientation is normal, as seen in figs. 13, 14, 15, Where the 
xylem faces the line ad. The wood is mesarch (fig. 17), with the 
Protoxylem gradually moving out toward the phloem as it ascends. 
the upper portion centrifugal elements are wanting, that is the 
wood is exarch (fig. 18). The vascular system of the cotyledon is 
differentiated relatively early in the development of the seedling. In 
that from which fig. 19 was drawn, in which no root has yet appeared, 
the vessels are fully matured. Worspe.t’s transfusion tissue was 
frequently observed in direct continuation with the centripetal xylem 
8. 18, ir), 
Mucilage canals are numerous in the lower part, and seem to bear 
no definite relation to the strands (figs. 30, 31); farther up they usually 
number one more than the strands and alternate with them; higher 
still they die out irregularly; in some cotyledons they are absent 
altogether, 
The vascular plate of the hypocotyl axis is irregularly four-sided 
" bikie in cross-section; all the xylem is in the center, sometimes in 
“solid mass, sometimes interspersed with pith cells. ‘The protoxylem 
= ints are clearly distinguishable. In the plant from which fg. 20 
drawn, the protostelic condition persisted through a vertical 
mtahce of 1.6™™, Above this the pith cells occupy the central 
"*8!0n, so that a siphonostele replaces the protostele (fig. 28). About 
