Bower . — Studies in the Phytogeny of the Filicales . VI. 31 
Hymenolepis — upheld under the same name. 
Photinopteris — upheld under the same name. 
Thus eight substantive genera now represent the old comprehensive 
genus. They are Acrostichum , E laphoglossum, Stenochloena , Polybotrya , 
Stenosemia, Hymenolepis , Photinopteris, and Leptochilus. To these should 
be added Platycerium , which was placed in an independent position by 
Hooker : Trismeria , which though placed by Hooker in Gymnogramme 
is actually * Acrostichoid ’ : and Cheiropleuria - 1 Note should also be taken 
of the genera Gymnogramme , Hemionitis , and Meniscium , as showing 
a soral construction not far removed from the c Acrostichoid ’, and liable to 
merge in it. 
These genera have been variously distributed by recent writers, notably 
by Diels (‘ Engler und Prantl,’ i, 4), Christ (‘ Farnkrauter ’), and Frau Eva 
Schumann (‘ Flora,’ 1915, p. 201). The opinions which they have expressed 
and the results arrived at by them will be here placed in relation with the 
conclusions derived from my own comparative studies. It will be best at first 
to account for the more outlying plants of Acrostichoid habit, referring them 
to their probable phyletic affinities. 
Taking first what remains of the old genus Acrostichum , there are three 
species — A. aureum , L., A. praestantissimum , Bory, and A. fasciculatum 
(Fourn.), C. Chr. To the latter the note ‘(an A. aureum?)’ is attached 
in Christensen’s Index. These Ferns have been held to be of very doubtful 
position. Diels ( 1 . c., p. 336) remarks that ‘ hardly anything can be made 
out as to the nearest affinity of this isolated type ’. This admission is 
remarkable in view of Sir William Hooker’s description of A. praestantis- 
simum? In the specific diagnosis he describes the sori as c covering the 
whole back of the pinnae, except the costa, and at other times confined to a 
narrow line at the margin as in Pteris , and then closely covered with 
a narrow pteridioid involucre \ This comparison is amplified in the text, and 
illustrated by Figs. 3, 4 on Plate LVIII, which also shows the venation. This 
sixty years old comparison has lately been elaborated by Frau Schumann, 
with valuable added detail. 3 It may be accepted that a highly probable 
phyletic sequence led from Pteris (Litobrochia) splendens , Klf., to A. prae- 
stantissimum, Bory, and on to A. aureum , L. The general habit, form of the 
leaf, and the venation are alike in them all, but the sorus spreads from the 
marginal commissure, as in Pteris , inwards upon the lower surface, giving 
the Acrostichoid character. This matter will be taken up again in the next 
memoir of this series. 
The case for Stenochlaena has been worked out developmentally in 
these studies. 4 Frau Schumann does not appear to have been aware of this 
(1. c., p. 245)3 but she arrives at the same conclusion from examination 
1 Studies, V. Ann. of Bot., 1915, p. 495. 2 Garden Ferns, 1862, Text to Plate LVIII. 
3 1. c., pp. 208-21, also p. 242. 4 No. IV, Ann. of Bot., vol. xxviii, p. 391. 
