Schizaeaceae from Eastern North America . 197 
Acrostichopteris , which is very similar in vegetative character, is best 
retained for the somewhat similar remains of fronds until definite informa- 
tion is obtainable regarding their reproductive structures, although it is 
extremely probable that some at least of the species of Acrostichopteris 
should be referred to the Schizaeaceae, and the same remark is equally 
applicable to certain species ordinarily referred to the genus Baiera } To 
mention a specific case, the homotaxial species Baiera cretosa of Schenk is 
very close to Schizaeopsis expansa , and was originally compared by Schenk 
with the modern Schizaea elegans. 
As has already been mentioned, there are abundant theoretical reasons 
for expecting to find representatives of this family as far back at least as 
the later Mesozoic. Such still earlier ferns as have been supposed to 
exhibit affinities with the Schizaeaceae are too obscure and indefinite to be 
of much value, and it seems certain that the older Mesozoic and Palaeozoic 
ferns, at least the Leptosporangiate ones, were too generalized to admit of 
their being referred to the accepted families based, as the latter are to such 
a large extent, upon existing species. There is, however, abundant col- 
lateral evidence for the view that by the dawn of the Cretaceous the main 
lines of cleavage which separate the families as we now know them were 
rather clearly defined. In addition to the Schizaea-Mke species here 
described, the Schizaeaceae were represented in the lower Cretaceous 
rocks of both Europe and America by several species referred to the genus 
Rnffordia , which in the character of its fructifications and sterile fronds 
resembles the modern genus Aneimia . There is of course the well authenti- 
cated Jurassic genus Klukia of Raciborski , 1 2 which seems to fall within this 
family, and Professor Zeiller 3 has recently called attention to certain fern- 
remains from the Wealden of Peru which show sterile fronds similar to 
those of Cladophlebis Browniana y which bore annulate sporangia of the 
Schizaea type. Stopes and Fujii 4 have also described structural material 
from the upper Cretaceous of Japan sufficiently preserved to show some of 
the soral characters and to warrant the restoration of the sporangium of 
what they have named Schizaeopteris mesozoica. While the genus Schizae- 
opsis is thus far confined to the eastern United States, the fern genus 
Acrostichopteris , which so closely resembles it in vegetative habit and 
geological range, has been found in the Kootanie formation of the western 
United States and in the Wealden of England, and identical forms have 
been described as various species of Sphenopteris from the lower Cretaceous 
rocks of Portugal by Saporta, 
1 This is, of course, not true of all species of Baiera , some of which, in their fruiting characters, 
show conclusively a relationship with Ginkgo. 
2 Raciborski: Englers Bot. Jahrb., vol. xiii, 1891, p. 1. 
3 Zeiller : Comptes rendus, tome cl, 1910, p. 1488. 
4 Stopes and Fujii : Philos. Trans. Royal Soc., vol. 201 B, 1910, p. 6, text-figs. 1-3, pi. ii, fig. 1. 
