1908] DORET Y—CERATOZAMIA 217 
geria. Of course the whole question resolves itself into the possibility 
of determining phloem in the absence of sieve plates. 
In the feature of anomalous thickenings, as in so many other 
features, Ceratozamia appears to hold an intermediate position. 
The extrafascicular cambium is clear and distinct, yet in plants with 
two scale leaves, two expanded foliage leaves, and two or three leaves 
developing, the secondary fascicular systems are entirely wanting. 
The failure or delay of this cambium to function indicates that it is a 
vestigial character. I have seen it in Zamia as clear and distinct, 
though not so abundant, as in Ceratozamia. 
There seems to be great variation in the number of root poles 
throughout the whole group of cycads and even in individual roots. 
his variation, taken in conjunction with the fact that in Ceratozamia 
the number depends upon the degree of development of the median 
bundle of the aborted cotyledon, indicates that this character is not 
to be depended upon as a phylogenetic one. 
Summary 
I. Ceratozamia is dicotyledonous, the second cotyledon being 
aborted by gravity. 
2. The cotyledon is often lobed at the tip. It is multifascicular, 
and all the bundles are derived from three. The wood is mesarch at 
the base and exarch in the upper portion. Mucilage ducts usually 
alternate with the bundles. 
_ 3. The leaf traces are at first vertical; girdling follows upon 
Mcrease in radial growth of the enclosed leaves and stem apex. 
The wood of the leaf traces is endarch in the central cylinder, but 
becomes mesarch in the leaf base and remains so to the tips of the 
pinnae. 
4. The scale leaves are aborted foliage leaves. 
5. The first-formed portion of the central vascular cylinder may 
bea protostele. 
6. The stem is a sympodium. 
7- There are several layers of extrafascicular cambium, but _ 
Seedlings two years old only the slightest trace of anomalous thick- 
ening, 
8. The root is a delayed organ, and its four poles are inserted 
"pon the cotyledonary bundles. 
