The Anatomy of Matonia sarmentosa, Baker. 305 
such a type is represented by Dipteris, which is admitted to bear a 
close relationship to Matonia (cf. Bower, 3, p. 618). Professor 
Seward and Miss Dale (10, p. 508) consider the connection to be 
most evident with M. pectinata in respect of frond-character. In 
the latter species the inner branch of each successive dichotomy 
becomes a pinna, the outer forks again : the final result being a 
regular “ scorpioid ” branch system. In M. sarmentosa , on the 
other hand, the modification of the primitive Dipteris form of 
dichotomy has taken place in a different way, the final form of the 
frond being much less stereotyped than in M. pectinata (Fig. 40). 
The rachis forks repeatedly, and one of two things may happen :— 
Fig. 41. A. Portion of rachis of frond, shewing an aborted bud and its 
two pinna;. B,C,D,E. Diagrams of a series of transverse sections in the 
region of branching of the rachis. Xylem shaded with lines, endodermis a 
dotted line, epidermis a continuous line, aborted xylem cross-hatched. 
