368 



MOSSES AND FERNS 



CHAP. 



The dome-shaped wall next formed is here not so marked, 

 being nearly flat. 1 No definite cover cell is cut off, but the 

 upper cell appears to divide by a single wall running obliquely 

 over the apex, somewhat as in Osmunda. The divisions in 

 the central cell offer no peculiarities, and the spermatozoids 

 resemble those of other Ferns. The archegonia are formed on 

 the forward part of the midrib, but are not confined to the 

 sides, as in Osmunda. Apparently a basal cell is not always 

 formed, but as to this and the much more important point, the 

 number and character of the canal cells, Rauwenhoff says noth- 

 ing definite. The neck is long and straight, like that of Os- 

 munda and the Hymenophyllacese. 



FIG. 210. A, Diagram of the tissues of the rhizome in Gleichenia flabellata, X8; B, 

 section of the stele (somewhat diagrammatic) of G. pectinata, Xz6; C, part of 

 the stele of G. dichotoma, X350. (All figures after Boodle.) 



In G. pectinata (Fig. 209) the resemblance of the anther- 

 idium to that of Osmunda is much more striking than in the 

 species studied by Rauwenhoff. The archegonium in this 

 species showed a division of the nucleus of the neck canal cell. 



1 Rauwenhoff's statement that the central cell of the antheridium con- 

 tains chlorophyll, to judge from his Fig. 58, which illustrates this, is based 

 upon a pathological case. The absence of chlorophyll from the central cells 

 of the antheridium is a very constant character in all Archegoniates. 



