1908] DORET Y—CERATOZAMIA 215 
tainty any line of demarkation between phloeoterma and stelar 
tissue. 
There are no anomalous thickenings in the roots of plants two 
years old. 
In general, mucilage ducts extend but a slight distance into the 
Toot, usually about 8™™, but in one specimen they were beginning to 
be formed in the plerome, immediately behind the region of its differ- 
entiation (md, fig. 42). 
The lateral roots are diarch. Fig. 40 represents a transverse sec- 
tion of a secondary root and the exit of a tertiary one. The upper- 
most lateral roots become ageotropic at a very early stage, and show 
symptoms of bacterial infection; and in some of the two-year-old 
plants, these roots present the characteristic ‘“‘coralloid” appearance 
indicative of algal infection. 
€ root, as was seen above, is late in developing. Fig. 27 
represents the position and form of the meristematic plate, which 
has given rise to stem above, but is yet inactive below. Fig. 19 shows 
the beginning of the activity which produces the root; the central 
portion of the active region in this figure is sketched in greater detail 
in fig. 41. In the stage represented in fig. 42, the root cap is devel- 
oped and the plerome and periblem initial groups are easily distin- 
guishable, but the plerome has not yet differentiated any xylem 
elements, 
While in older seedlings the vascular systems of stem and root seem 
'o be continuous, one sometimes finds sections which indicate a certain 
amount of interruption. Such a case is shown in fig. 43.’ 
Discussion 
The result of the experimental work on Ceratozamia places this 
8enus in line with the other cycads with reference to the dicotyledonous 
* When this investigation was completed, MATTE (7) published a preliminary 
note on the same subject. He says that the petiolary bundles have the @ arrange- 
ment, that there is an anterior fascicular system in the region, of insertion of the rachis, 
_ that the pinna has terminal teeth. These features do not appear in any of my 
Speaking of the root, he says it is tetrarch, and that he has observed a 
Progressive reduction of poles, to three and even to two. As I have observed, no 
tria “tion occurred in the roots of any of the seedlings I sectioned, and the root 1s 
4 th as often as it is tetrarch. He has also found the abnormal thickenings strongly 
ped; but he does not give the age of the seedlings which manifest them. 
