Bower.— Studies in the Phytogeny of the Filicales. VI. 25 
vascular twigs ending blindly within them. They are all rhizomatous, creep- 
ing or climbing forms, often with a thick fleshy axis. Their mature leaf 
architecture shows more or less clear reference to a dichotomous origin, 
with sympodial development, often with a helicoid element in it. It is seen 
that anatomically they all may be derived from the solenostelic type, 
by varying degrees of breaking up of the leaf-trace, and of the axial stele by 
perforations as distinct from the leaf-gaps. Their dermal appendages are 
often scales, but these are referable in origin to simple hairs, such as are 
actually seen in Dipteris and Cheiropleuria. They all have superficial sori, 
but according to the extent of their spread from the definite vascular 
receptacle over the leaf-surface, these Ferns have been segregated as Polypo- 
dioid or Acrostichoid. The view here advanced is that they constitute 
a natural phyletic group of Dipterid derivatives which might be styled the 
Dipteroideae. 
A second series, which probably took a more or less parallel, but 
phyletically distinct line of progression, is found to be related to Metaxya 
as its approximate source. It includes Syngramme and E laphoglossum , and 
it also involves a progression from a circumscribed sorus to an Acrostichoid 
state. An obvious character marking off these Ferns from the Dipteroideae 
is their venation, which is simply pinnate, either without fusions ( Metaxya ), 
or with few or many of them, but always without any free-ending twigs 
within the areolae thus formed. Metaxya has already been described 
at length. 1 Its relatively primitive characters are the unbranched hairs, 
solenostelic axis, undivided leaf-trace, flat receptacle, and simultaneous origin 
of its sporangia, which have an almost vertical annulus, interrupted at the 
insertion of the stalk. These characters keep it apart from Alsophila, with 
which it has commonly been classed. Presl established it as a distinct 
genus. He also noted 2 that not uncommonly more than one sorus may be 
borne upon each vein, which is exceptional among Ferns. This state is 
exemplified by Plate II, Figs. 9, 10, which show also the free Pecopterid 
venation, and the way in which the sori may be extended along the vein into 
oblong form. From this condition it is but a slight step to that seen in 
Syngramme , which was included as a sub-genus in Gymnogr amine, in the 
‘ Synopsis Filicum ’ (p. 386), but is retained as a substantive genus by Diels, 
and ranked in his Pterideae-Gymnogramminae. 3 Its position as a substantive 
genus is now generally accepted. 
Syngramme, J. Sm. 
The genus includes about twelve species of rare and local Ferns from the 
Malayan region. Hooker remarks that they have the habit and mode 
of growth of E u-polypodium. They have mostly a short creeping rhizome 
1 Studies, III. Ann. of Bot., vol. xxvii, 1913, p. 443. 2 Tentamen, p. 59. 
3 Engler u. Prantl, i, 4, p. 257. 
