oon BERRY: A MIDDLE EOCENE GONIOPTERIS 
mostly tropical, ferns, variously segregated or aggregated by 
students of existing ferns in the genera Lastrea, Nephrodium, 
Phegopteris, Polybotrya and Drvyopteris. 
Christensen, perhaps the foremost living fern student, enu- 
merates upwards of one thousand existing species which he refers 
to Dryopteris. These are segregated into ten groups termed 
subgenera, although most of them are admittedly of generic rank. 
These groups of species are named Eudryopteris, Stigmatopteris, 
Ctenitis, Lastrea Bory (emended), Glaphyropteris Presl, Steiropteris, 
Cyclosorus Link (emended), Leptogramma J. Sm., Goniopteris 
Presl (emended), and Meniscium (Schreber). 
The fossil species here described belongs to this author’s ninth 
subgenus, the emended Goniopteris of Presl, which I am recog- 
nizing as a valid genus, since the data which paleobotany furnishes 
to recent botany are obscured by the use of generic names that 
denote composite aggregations of living species like so many of the 
fern genera in Die Natiirlichen Pflanzenfamilien. Goniopteris as 
delimited by Christensen* has about three score, mainly American 
tropical species, although it is represented in the Old World by at 
least two species of Africa, Asia and Australia. It is an eminently 
natural group that has evidently inhabited southeastern North 
America since the middle Eocene. 
The present type belongs with those fossil forms characterized 
by a single well marked lateral running to the tip of each lateral 
lobule and these laterals are more often opposite or subopposite 
than alternate. Each lateral diverges from the midrib of the pinna 
at an angle of about sixty degrees and gives off, alternately proxi- 
mad and distad, simple branches, averaging about eight to ten to 
a side. The basal distal tertiary of one lateral unites with the 
basal proximal tertiary of the adjacent superior lateral somewhat 
above the median point between the two laterals. This united 
vein, termed a ray by Ettingshausen, proceeds in a flexuous course 
to the marginal sinus, uniting alternately with the distal and 
proximal tertiaries from the adjacent laterals. In the marginal 
lobe there are several simple and free tertiaries, usually three or 
four oe to the distal margin and four to six running to the 
* Christensen, Carl. On a natural classification of the ats of Dryopteris. 
Bienes. Arbeijder Tilegnede Eug. Warming, 73-85. NI 
