158 
BEAUTIFUL FERNS. 
appear as little whitish scales on the back of the veins. It 
occurs in almost all places where the plant is common, is 
often produced from root-stocks which bear also normal fronds, 
and presents all gradations from the usual sterile frond to the 
proper fertile one. Ragiopteris onocleoides of Presl is founded 
on a young fertile frond of this species placed with a sterile 
one of what Milde judges to be a monstrous form of Aspi- 
dumi Filix-mas. Maximowicz describes a var. interrupta, from 
the Amoor region, in which the fertile frond nearly equals' the 
sterile, and has elongated pinnae, with remote segments. This 
condition is also sometimes seen in American specimens, and 
is hardly a true variety. 
In an article on “The late Extinct Floras of North 
America,” which appeared in Vol. ix of the Annals of the New 
York Lyceum of Natural History, in April, 1868, Professor 
Newberry describes certain fossil specimens of ferns occurring 
in Miocene argillaceous limestone at Fort Union, Dacotah, 
and refers them with little hesitation to this species. I have 
not seen the specimens, but, as similar venation and not very 
dissimilar fronds are seen in Woodwardia and Pteris, one 
may perhaps doubt the absolute certainty of the identiheation. 
