524 Bower.—Studies in the Phytogeny of the Filicales . 
A minor character which also indicates a primitive state is that the 
dermal appendages are all hairs. Flattened ramenta are absent, though 
they may be found even in some Gleichenias . As compared with the hairs 
oi Matonia and Dip ter is, those of Cheiropleuria are simpler, and suggest that 
in this feature it is the most primitive of them all. 
The comparisons given in detail above have shown that, as regards the 
sorus, Cheiropleuria is an advanced type. This is seen from its ‘ Acrosti- 
choid ’ soral areas, and from the f mixed ’ condition of the sporangia. But 
the comparison instituted through examination of the vascular supply shows 
that the state seen in Cheiropleuria is relatively primitive compared with 
that seen in Dipteris and Matonia , though closely resembling that seen in 
Gleichenia . The sori of all of these are superficial, and Dipteris , with its 
variable soral conditions, gives the connecting clue between the simple state 
in Gleichenia and Matonia , and the ‘ Acrostichoid ’ state of Cheiropleuria . 
The arrangement in D. Lobbiana is clearly conformable to that of Matonia 
and Gleichenia. The advance seen in D. quinquefurcata leads, with the 
addition of the webbing of the frond, to that seen in D. conjugata , with its 
enlarged leaf-surface. Upon this the numerous sori retain their identity; 
but in Cheiropleuria that identity is lost, and the result is seen in the 
large continuous fertile patches. Such progression from a state with 
discrete sori to the merged, ‘ Acrostichoid ’ state finds its parallel in 
several other phyletic lines in Ferns. (Compare Annals of Botany, 
1914, p. 437.) 
In their sporangial characters Cheiropleuria and Dipteris are closely 
alike. The most striking point of that similarity lies in the four-rowed 
stalk, which so readily results from the peculiar cleavage of the sporangial 
primordium by alternate segments ranging in two rows. The resemblance 
of the genera in a character so remarkable is the strongest possible evidence 
of correctness of the comparisons based upon other features. 
Taking all the characters together, the conclusion seems fully justified 
that Cheiropleuria is a Fern of Matonioid-Dipterid affinity. That while 
it has retained a primitive type of dermal appendages, and a vascular 
structure of its axis such as is seen in the presumable Gleichenioid ancestry, 
it has adopted a type of leaf and of sorus which are seen in the relatively 
advanced species of Dipteris , but has carried these features to a still more 
advanced state than is seen in any member of that genus. It is a striking 
example of the absence of strict parallelism of advance'in the several criteria 
of comparison. But at the same time the incongruity of its characters marks 
it out as one of the most interesting synthetic types to be found among 
living Ferns. 
Turning now to the relation of Cheiropleuria upwards in the scale, that 
is to forms which, though probably related, show collectively characters 
of still further advance than Cheiropleuria itself does, these are found 
