1908] THIESSEN—DIOON EDULE 359 
given by METTeNrus. It was the first correct statement of the facts, 
but their meaning was probably not understood until an interpreta- 
tion of the situation was given in 1886 by BERTRAND and RENAULT (5). 
The second paper upon the vascular anatomy of Dioon is that of 
Matte (6), a brief description of the anatomy of two seedlings being 
given. In one of them, a very young seedling, the cotyledons were 
unequal, the larger having four vascular bundles, and the smaller 
having two small bundles, but with two other very small strands at the 
very base, one on each side of the other bundles. The bundles con- 
tinue in a vertically descending course until where the foliar bundles, 
alter being arranged in a circle, have been reduced to four large 
bundles, separated by medullary rays. The six cotyledonary strands 
turn now abruptly toward the three poles (protoxylem groups) of 
the root, converge, and unite two by two in front of them, effecting 
an entrance through the medullary rays separating the foliar bundles, 
and unite their phloem with the phloem of the stem. Their second- 
ary xylem unites laterally with that of the stem, while the primary 
Xylem seems to be in direct continuity with the tracheal poles (pro- 
toxylem groups) of the root. The centripetal xylem disappears in 
the Passage across the medullary rays. 
In the description of the older seedling Matte found in each 
cotyledon four bundles of equal size. Their course and method of 
union js comparable with that found in the other seedling, and they 
still unite two by two in converging toward the poles (protoxylem 
8roups), but these poles are four in number. 
_ Marte touches also upon the girdling habit, ascribing it to an 
itercalary growth produced under the influence of the development 
of new interior leaves. The vascular strands of the youngest leaves 
Pursue a vertical course, but those of the older ones an oblique 
Souitte, a comparison of leaves of different ages showing that this 
departure from a direct course is due to intercalary growth. 
Methods 
Embryos were removed from mature seeds and killed in chromo- 
acetic acid, imbedded in paraffin according to the usual methods, 
s with a rotary Minot microtome, and mounted in series, much care 
“ing taken that no sections were lost or misplaced. When only the 
