Igor] ANATOMY OF THE OSMUNDACEAE oy OS 
irregular fragments of matter are found in the cell, which also 
stain a similar brown. The relation between these fragments, 
the ‘‘globules brillants,” the callus, and the disappearance of the 
nuclei calls for further investigation. 
The sieve plates are very numerous, and vary in size and 
form. The walls of the pits are abrupt, and the number of pits 
varies with the size of the plate. The larger plates are irregu- 
larly oblong and the smaller ones are round. In Todea they are 
largest and most numerous. Having described the sieve tubes 
at some length, we shall now examine their distribution. 
The phloem forms a continuous sheath, the outer portion of 
which is the protophloem. To this peripheral part of the phloem 
I find that DeBary and Zenetti alone make specific reference. 
The former states* that this region of the central cylinder is 
characterized by ‘“ quergestreckte Zellen,” but he offers no opin- 
ion as to the nature of the tissue in question. Zenetti divides 
the zone into strands of typical protophloem and connecting 
portions of ‘‘quergestreckte Zellen.”” The typical protophloem 
is in short strands one cell thick, lying ectad of strands of xylem 
which are about to give off the leaf traces. The ‘‘quergestreckte 
Zellen” he cannot recognize as sieve tissue, because of the ‘ quer- 
gestreckt”’ form and the position of the cells. This tissue in 
Osmunda regalis, consequently, forms a cylinder interrupted by 
the strands of protophloem only, but Zenetti found it to be gen- 
erally two cells in thickness and opposite the medullary rays 
often several cells deep. 
I have ascertained that the ‘‘quergestreckte Zellen” are 
devoid of nuclei; their walls are of cellulose, staining violet or 
blue with iodin solutions. They are rounded, elongated ele- 
ments, with more or less oblique terminal walls; and are char- 
acterized by the possession of sieve plates which show the callus 
reaction when treated with Russow’s reagent; the cells contain 
an abundance of ‘globules brillants’’ which are aggregated 
especially about the plates; the protoplasm is reduced to a thin 
parietal layer. The characters of the typical protophloem cells 
*° DEBARY :. of. cit, 360. 
