1901] ANATOMY OF THE OSMUNDACEAE 401 
side the protophloem is separated from the metaphloem by paren- 
chyma. There are no “quergestreckte Zellen.” The pericycle 
consists of two or three layers of cells, and is bounded by a well 
developed endodermis continuous with that of the stem. With 
reference to the attachment of the leaf trace to the cauline 
vascular axis Zenetti has given a very careful and accurate 
description.” 
Strasburger has held”? that the stele of the petiole of 0. 
regalis is a collateral bundle. He has considered the inner band 
of metaphloem to be a parenchymatous tissue. However, the 
cells of this band prove to be characteristic sieve tubes, and are 
continuous with sieve tubes in the stem opposite the medullary 
rays. The leaf traces, therefore, are undoubtedly concentric. 
Several botanists have arrived at the same conclusion for Q. 
regalts 73 24 
In summary, the most important features of the leaf trace 
are: (1) the absence of a pith, (2) the endarch xylem strand. 
(3) the concentric type of stele, (4) the absence of ‘ querge- 
streckte Zellen,” and (5) the cylinder of protophloem completed 
on the inner face by a band of metaphloem. 
THE ROOT. 
The roots have a definite relation to the leaves, both in posi- 
tion and in numbers. Two roots invariably originate from the 
base of every leaf trace, or from the central cylinder immediately 
below. They come off at the same level, one opposite each arm 
of the horseshoe-shaped strand of xylem ( fig. 18) in every case 
where there are just two roots to a leaf. They grow almost 
directly outwards, and so in a transverse section of the stem are 
cut longitudinally. In such a section it is seen, likewise, that 
the cortical tissues of the stem and root are entirely independent 
of each other, and that, therefore, the root is of endogenous 
Origin. This fact is true of the secondary roots also. 
* ZENETTI: of. cit. 69. 
* STRASBURGER : of, cit. 448. 
3Scorr; op. cit, 319. 
* ZENETTI : of. cit. 66. 
