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BOTANICAL MUSEUM LEAFLETS 
HARVARD UNIVERSITY 
Campriver, Massacuuserrs, Frnrvary 9, 1940. Vor. 8, 1 No. 1 
THE FOSSIL FLORA OF IOWA COAL BALLS 
Ill. Corpalantruvus 
BY 
Wituiam C. DarRaAH 
THE two most ancient, primitive and extinct orders 
of gymnosperms are known as the pteridosperms or seed 
ferns and the cordaites. The pteridosperms are not strob- 
iloid because the sporangial organs are borne pinnately, 
not spirally or whorled. The cordaites, on the contrary, 
have short axes (branches) bearing a number of small, 
spirally disposed ‘‘strobili’’ or ‘‘inflorescences.’’ In fact, 
the interpretation of these structures has been a contro- 
versial problem for nearly seventy years. 
There have been two chief limitations imposed upon 
the investigation of the fructifications of the Cordaitales, 
one being the excessive rarity of structurally preserved 
specimens, though so-called impressions have been fairly 
abundant ; the other limitation being the narrow point of 
view of the plant morphologist, who by necessity has in- 
terpreted the fossil remains. Since the cordaites possessed 
a construction similar to that of the coniferophyte body, 
it was natural that comparisons would be made with the 
strobili of existing coniferous and gnetalean types. Pa- 
leobotanists are endeavoring constantly to go back to an- 
tiquity and describe the earliest forms and to suspend 
judgment upon homologies until the extinct forms are 
adequately understood. 
[1] 
Pertinent. A 
