394 BOTANICAL GAZETTE | DECEMBER 
”” 
are the same as those of the ‘‘quergestreckte Zellen 
regard to orientation (fig. 6). 
Transverse sections show that the long axes of the so-called 
‘‘quergestreckte Zellen” are tangentially placed, and never radi- 
ally to any degree. To determine the slant of the long axes, 
therefore, with reference to the axis of the stem, tangential sec- 
tions must be made. If such be examined it is seen that some are 
exactly at right angles to the axis, others are almost or entirely 
parallel, and between these extremes there is every gradation. 
This at once explains the difference in “width” of the ‘‘quer- 
gestreckte Zellen’”’ in transverse section. It is further to be 
noted from the tangential sections that the ends of typical pro- 
tophloem cells never abut against the long sides of the ‘ quer- 
gestreckte Zellen,” but there is a gradual change in the direction 
of the latter so that their ends communicate with the proto- 
phloem and it is quite impossible to say where the typical proto- 
phloem ends and the “quergestreckte Zellen” begin. 
The root and leaf have been examined for ‘‘ quergestreckte 
Zellen,” for if these elements constitute a characteristic textural 
feature of the Osmundaceae they would naturally occur elsewhere 
than in the stem. They are not present at all in the appendicular 
organs. Further, in the young sporophyte, where the leaf gaps 
are far apart, they are absent from considerable portions of the 
stem. The real nature of the ‘“quergestreckte Zellen” will be 
discussed after observations on their development and their rela- 
tion to the leaf traces have been described. 
The ‘‘quergestreckte Zellen” and the typical protophloem 
cells form a continuous sheath in all the species studied. In O. 
Claytoniana the elements of this sheath are very much smaller, 
and so it is easier to distinguish them from the metaphloem. 
In 7. barbara their histological characters are best studied 
because of their relatively large size. Frequently in O. cinna- 
momea and O. regalis it is difficult to decide in the mature stem 
whether or not certain cells belong to this sheath or to the 
metaphloem. But evidently in all of the species the sheath is 
rarely more than two cells in thickness, and often, especially in 
except in 
