MATONIA-DIPTERIS SERIES 621 
show no regularity of position or of orientation, such as is seen in Matonia: 
there is also an absence of any projecting receptacle. The sporangia of 
the same sorus have been found to arise simultaneously in D. Loddiana, 
which may in this respect compare with Masonia. But in D. conjugata 
they are formed successively, while those which appear later are distributed 
without order amongst those first formed. The sorus, in this respect, 
compares with that of the Mixtae, but the succession is not long main- 
tained. When the individual sporangia are examined an_ essential 
difference is found from the Polypodiaceous sporangium, with its vertical 
ring; for here the annulus is not only oblique, but also twisted: the series 
of cells of the annulus can be traced laterally past the insertion of the 
stalk, but the induration of their walls is interrupted at that point: the 
Fic. 346. 
Dipteris conjugata, Rein. Portion of leaf, showing the extended surface, the webbing 
between the pinnae, the venation, and the numerous sori spread over the surface. 
Natural size. Figs. 344-346, after drawings by Mr. A. K. Maxwell. 
dehiscence is lateral, but there is no clearly defined stomium. The 
sporangium itself is small, and the spore-output has been found both in 
D. Lobbiana and in YD. conjugata to approach the typical number of 64. 
Comparing this sporangial structure with that of other Ferns, it is actually 
most like that of the Cyatheae, though the interrupted induration of the 
annulus points a further departure from the primitive type, such as may 
with reasonable probability be found in the sporangia of AZatonia, and 
ultimately of Glecchenia.* 
Turning to the anatomical characters, they bear out the above com- 
parison ; for the rhizome contains a simple solenostele, while the leaf-trace 
comes off as a single ribbon-like strand, opening a leaf-gap which soon 
closes again. The margins of the petiolar strand curve inwards to form 
the usual horse-shoe curve, which only breaks up at a point close below 
1See Miss Armour, Mew Phytologist, 1907. 
