212 SYMMETRY OF THE SPOROPHYTE 
in all the genera of Marattiaceae investigated hitherto is upright, bursting 
through the prothallus, not recumbent as in other Ferns (Fig. 105). In 
Angiopteris and Maratta this con- 
dition is maintained throughout life, 
and there is no reason to think other- 
wise than that these plants retain 
their primitive position. It is probably 
shared also by Archangiopierts ;1 at 
all events there was no dorsiventrality 
in the only specimen with an axis 
hitherto examined. In the genus 
Danaea the same holds for JD. 
simplictfolia ; but certain other species 
; i ; of Danaea have an oblique rhizome, 
te ee ee ee for instance, Danaea alata (Fig. 106). 
aa commissure. (After Gwynne: Comparison of a number of stocks of 
this Fern shows various degrees of 
inclination and curvature of the axis. It is upright at first, and produces 
leaves and roots uniformly on both sides of the axis; but later the axis 
arches over to one side, and a distichous arrangement of the leaves is 
approached, while the roots originate chiefly from .- 
the side directed downwards. In Kauéfussia these ee wee 
characters are more pronounced; for there the Loe ge? 
mature rhizome is horizontal, with marked dorsi- 
ventrality, and with internodes of appreciable / 
length (Fig. 107). Unfortunately the early | 
development of the sporophyte of Kawz/fussia is | 
\ 
i 
Fic. 107. 
still unknown. It seems ag reasonable interpre- 
tation of the facts that the upright position, with 
radial symmetry, as seen in Angiopteris and 
Marattia, was the primitive condition here as in 
f fl 
other Vascular Plants: and that the oblique ¥ 
position, already seen in certain Danaeas, became 
more accentuated in the horizontal rhizome of t 
Kaulfussta, with its marked dorsiventrality. a 
The analogy with what is seen in the Ophio- 
Fic. 108. 
glossaceae greatly strengthens this conclusion. As 
in the Marattiaceae, so also in all the genera of eee nee 
the Ophioglossaceae the axis is from the first ae i a 
upright (Fig. 108); and that position is maintained - 
throughout life in Ophzoglossum and Botrychium, But in Helminthostachys, 
notwithstanding its originally vertical position, the axis of the mature 
plant is markedly dorsiventral’ (Fig. 109), with distichous arrangement 
of the leaves. The conclusion which naturally follows is that in the 
}Gwynne-Vaughan, Azz. Bot., xix., p. 260. 
