370 Bower . — The comparative examination of the 
position being definitely fixed at present : at the same time I 
may state that, as far as my observations on the meristems 
extend, they appear to correspond to the Polypodiaceae. The 
Schizaeaceae are recognised as those among the truly lepto- 
sporangiate Ferns which show affinities to the eusporangiate 
Ferns, while the Osmundaceae show that affinity much more 
distinctly, and most recent writers admit more or less fully 
that they form a connecting link between the leptosporangiate 
and eusporangiate members of the series. 
But these conclusions, based chiefly upon the comparison of 
the sporophyte, are also borne out by the characters of the 
oophyte : thus the filamentous, protonema-like character of the 
oophyte of the Hymenophyllaceae is the simplest in struc- 
ture of all the prothalli of Ferns, and indicates their relation to 
the Bryophyta h The prothallus of the Polypodiaceae, after 
a short filamentous growth, widens out into the cordate ex- 
pansion with circular 4 cushion ’ ; the Cyatheaceae resemble 
them in these respects 2 ; the Schizaeaceae also appear to 
correspond to the Polypodiaceae in the characters of the 
prothallus 3 , and this, as well as other grounds of comparison, 
lead me to conclude that their affinity to the true leptospor- 
angiate Ferns is nearer than to the Osmundaceae. In the 
Osmundaceae the result of germination may be directly a 
massive prothallus, the filamentous stage being here lost 4 ; 
often, however, the prothallus of these plants may first assume 
a flattened form. In the Marattiaceae the first result of 
germination may occasionally be a short filament, or more 
frequently a flattened expansion ; but often the direct result is 
a massive body which, when the prothallus is mature, is 
thicker than that of the Osmundaceae 5 . Lastly, as far as it 
is known, the oophyte of the Ophioglossaceae is a solid, mas- 
sive body. Though in comparison of the oophyte it is not 
1 See Bower, Annals of Botany, Vol. I, p. 270, where the most important litera- 
ture on this subject is quoted. 
2 Bauke, Pringsh. Jahrb. Bd. X, pp. 49, etc. 
3 Sadebeck, in Schenk’s Handbuch, I, p. 17°- 
4 Luerssen, Zur Keimungsgeschichte der Osmundaceen. 
5 Jonkman, La Generation Sexuee des Marattiacees. 
