Filicales. 
2 5 1 
solenostele, yet we know from the fossil record that the type of 
branching of the fronds of Matonia was characteristic of its Jurassic 
allies. It seems not unlikely that the solenostele of Dipteris 
originated with the Polypodiaceae, the order in which the genus 
is usually included, but if in accordance with Mr. Seward and Miss 
Dale, supported by Professor Bower, we make Dipteris into a 
separate order, the Dipteridineae, the near allies of this order would 
seem to be the simpler Polypodiaceae and the Gleicheniaceae, and 
not as Professor Bower suggests the Matonineae. To the Polypo- 
diaceae Dipteris shows its affinity in its anatomy, while it approaches 
Gleichenia in the dichotomy of its frond (although the axillary bud 
of the latter genus is not represented in Dipteris) and in its mesarchy. 
The solenostele of Gleichenia pectinata appears however to be a 
recent development of the genus and to have originated indepen¬ 
dently of that of Dipteris. 
As regards the relationship of the Cyatheaceae to the Polypo- 
diaceae it is impossible to doubt their close affinity. The vertical 
annulus found in most Polypodiacete seems to be less primitive 
than the oblique annulus of the Tree Ferns; the regular basipetal 
succession of sporangia on the receptacle also appears to have been 
lost by some Polypodiacete. On the other hand the tree-like habit 
of the Cyatheaceae appears to be a recently acquired character. 
LITERATURE QUOTED. 
1 . 
2 . 
3 . 
4 . 
5 . 
6 . 
7 . 
8 . 
E. A. Newell Arber. “On the Past History of the Ferns.” Annals of 
Botany, 1906. 
H. M. Armour. “On the Sorus of Dipteris." New Phytologist, 1907. 
L. A. Boodle. “Comparative Anatomy of the Hymenophyllaceae 
Schizaeaceae and Gleicheniaceae. I. On the Ana¬ 
tomy of the Hymenophyllaceae.” Annals of 
Botany, 1900. 
,, Ditto. “ II. On the Anatomy of the Scbizaeaceae.” 
Annals of Botany, 1901. 
,, Ditto. “ III. On the Anatomy of the Gleicheniaceae.” 
Annals of Botany, 1901. 
,, Ditto. “IV. Further Observations on Schizcea." Annals 
of Botany, 1903. 
F. O. Bower. “ Studies in the Morphology of the Spore-producing 
Members. IV. The Leptosporangiate Ferns.” 
Philosophical Transactions of the Royal Society of 
London. Series B, Vol. 192, 1899. 
,, Ditto. “V. General Comparison and Conclusion.” 
Philosophical Transactions of the Royal Society of 
London. Series B, Vol. 196, 1903. 
,, “The Origin of a Land Flora.” Macmillan & Co., 1908. 
9 . 
