1908] DORET Y—CERATOZAMIA 205 
older plants by WorsDELL (19), who seized the occasion to emphasize 
the similarity to the Medullosae. 
In 1904 Marre (6) published his masterly thesis, which in the 
third part treats of the seedlings of Dioon edule Lindl., Cycas sia- 
mensis Miq., and Encephalartos Barteri Carruth. Of his two seedlings 
of Dioon edule one proved abnormal, one cotyledon being partly 
aborted. The cotyledonary bundles are mesarch near.the base, but 
the protoxylem moves quickly outward, so that the bundles are exarch 
throughout most of their course. The axis is considered as an aggre- 
gation of leaf bases, and the girdling is explained as being due to 
intense intercalary growth produced under the influence of the 
developing leaf within. The four root poles are inserted upon the 
cotyledonary bundles, the median bundles furnishing insertion for 
two diagonally opposite poles, and each lateral trace uniting with its 
mate of the other cotyledon to furnish insertion for the other two 
poles. Mucilage canals are reported in the root, for the first time in 
acycad. The root of Cycas siamensis is diarch; its two poles are 
inserted upon the median bundles of the cotyledons, the lateral 
bundles dying out in the cortex. Anomalous thickenings or cortical 
vascular strands are conspicuous; Marre’s demonstration that 
these are not abnormal, but merely remnants of an ancestral charac- 
oa justifies his objection to the term “anomalous” used to describe 
them, 
In Encephalartos the root is pentarch, and the cotyledonary 
bundles—a single, ringlike trace from each of the three cotyledons— 
use with the leaf traces at different levels before entering the central 
cylinder. This cylinder is polystelic, as in Medullosa anglica Scott. 
In considering this feature, Matre indorses WoRSDELL’s view that 
it helps to relate the Cycadales to ancient forms like Medullosa 
tather than to monostelic forms like Heterangium as Scot suggests. 
He regards the root of cycads as a “new organ” inserted upon the 
— extremity of the hypocotyl, and not merely an extension of that 
Tgan, 
The main facts discovered by these investigations, and agreeing, 
- far as they relate to Dioon edule, Cycas, and Zamia, with — 
lished Studies made in this laboratory by LAND, THIESSEN, = 
May be classified as follows: 
