Campripcr, Massacnusetts, Marcu 11, 1938 
oy ARD core 
vr ope 
MARK 11 1938 
N 
UM LEAFLETS 
HARVARD UNIVERSITY 
A NEW FOSSIL GLEICHENIACEOUS FERN 
FROM ILLINOIS 
BY 
Winttiam C. Darran 
‘THE ONLY KNOWN GENUus of Paleozoic ferns attribut- 
able to the family Gleicheniaceae is Oligocarpia Goep- 
pert. The sorus is of the gleicheniaceous type although 
the complete details of its anatomy are insufficiently 
known. The genus has been the subject of considerable 
study because of its great antiquity and significant rela- 
tionship. Oligocarpia is probably exclusively Paleozoic in 
age but several authors have included Mesozoic species 
in the genus. 
The living Gleicheniaceae include two genera and 
eighty species. Gleichenia has seventy-nine species which 
are chiefly distributed in tropical regions, and Stroma- 
topteris, endemic to New Caledonia, is monotypic. No 
species of the family occur in the existing north temper- 
ate flora. 
Sometimes a third genus, Platyzoma, is recognized. 
This genus contains only one species occurring in north- 
ern Australia. 
The oldest undoubted Gleicheniaceae occur in the 
Triassic of Switzerland, and soon thereafter the group 
became widely distributed over the world. It seems pro- 
bable that the family attained its maximum development 
during Cretaceous times, and that it has gradually de- 
clined since the beginning of the Cenozoic. 
[ 145 ] 
Vor. 5, No. 8 
Ave e! o Sasadanag 4 ep lB! ir oq 
a) 
