1gtt] CHARLES—ANATOMY OF MARATTIA 95 
though sometimes triangular in cross-section, in the apex of the 
young stem of Angiopteris, and BREBNER (3) concluded that 
Danaea was the same. 
Such differences of opinion show that there is either variation 
or vagueness in the structure observed. In this case both enter 
into the result. In very young stems there is a triangular pyra- 
midal apical cell (fig. 31). This soon becomes prismatic, and the 
outline of the triangle in cross-section becomes irregular (fig. 32). 
Gradually it becomes four-sided (fig. 33). Then one of the latest 
segments begins to act as an apical cell, and there are two blocks 
of meristematic cells at the apex (fig. 34). In longitudinal view 
two sections separated from each other show two large vacuolate 
cells cutting off segments from the base. The division of the 
segments is very irregular. In a still larger stem the apex was 
occupied by a meristem (fig. 35). 
The growing point of the young stem is close to the base of the 
youngest leaf and very narrow (fig. 36). As the stem grows older 
the apex grows broader. At the solenostelic stage the tissue 
below the center of the apical cell is large-celled pith (fig. 37). 
The root apex has received more attention than that of the 
stem. The three-sided cell, probably derived from the octant 
of the embryo, has been observed in Angiopteris. A similar cell 
occurs in the apex of the very young primary root of Marattia. 
As in the stem, a four-sided prism soon appears, which 
Hote (14) thought was permanent. SCHWENDENER (25) held 
that it divided into four about the axis of the root, and BowER 
(2) agreed with him. Russow (23) found a group of initials. 
Kocu’s (16) explanation for the different situations that occur 
is ingenious. The evidence, however, of a regular sequence of 
divisions and fan-shaped growth of one segment with consequent 
shifting to the center is not entirely convincing. A possible 
explanation is that there is no fixed structure or behavior in the 
apex of the root. 
New roots originate in the meristematic region of the stem before 
differentiation of tissue has begun. FARMER and HIL1 (Q)*main- 
tain that the origin is a single six-sided prismatic cell of the endo- 
dermis cutting on the sides and ends. According to DE Bary (6) 
