smaller than those found in Botryopteris forensis from 
St. Etienne, France. I have before me, two ground sec¬ 
tions of detached sporangia collected in 1935 from Com- 
berigolle (Grand ’Croix) near St. Etienne, prepared by 
one of my students, Mr. William S. Benninghoff. The 
spores in these sporangia have a maximum diameter of 
0.07 mm. and agree in size with the recordings of Renault. 
The sporangia in the Iowa specimens are much less elon¬ 
gate, more nearly spherical. In other details such as the 
annulus, sporangial wall, attachment and spore number, 
the two forms are very similar. 
Comparison with other Botryopterid sporangia 
In 1902, Oliver (14) described a remarkable vascular 
sporangium from Grand’Croix which he was inclined to 
refer to Botryopteris , perhaps even Botryopteris forensis, 
assuming that the preservation of his specimen could 
have been better than that of Renault’s types. How¬ 
ever, the spores in this sporangium have a diameter of 
only 0.02 mm., instead of 0.06 to 0.07 mm. as in Botry¬ 
opteris forensis. The unusual tracheidal nature of the cells 
of the outer wall, at once distinguishes this specimen 
from the Iowa form. 
Renault (15) also described sporangia under the name 
of Botryopteris dubius , which are characterized by an 
elaborate sporangial wall, at least two layers in thickness, 
of which the outer is three or four cells deep. The spores 
have a diameter of 0.08 mm. The Iowa specimens have a 
much more simple wall and much smaller spores. Renault 
subsequently (17) referred this form to Zygopteris. 
Description of the specimens 
On the first plate, the figure at the top shows the 
broken surface of a mass of sporangia in a vertical plane 
beyond, i.e. outside of, the axis. In other words it pre- 
[160] 
