i 
f 
> 
PARDVADT) ® 
f HARVARD | 
[ LEAFLETS 
HARVARD UNIVERSITY 
CampripGe, Massacnusetts, Marcu 4, 1941 
THE FOSSIL FLORA OF IOWA COAL BALLS 
IV. LEprpocaRPon 
BY 
WitiuraMm C. Darrau 
Seeds and seed-like bodies have been observed in all 
of the coal ball floras of the world. Krick (7), Reed (10), 
Schopf (11), and Darrah (2) have recorded numerous 
forms from various American localities. Recently in the 
progress of our investigation of Iowa coal balls, large 
numbers of smooth seeds or seed-like structures without 
any prominent scars or markings were isolated from the 
matrix by mechanical means. These rather large organs 
are somewhat flattened and elongate. A typical specimen 
is approximately 12 mm. long, 8.5 mm. wide, and 7 mm. 
thick in a median plane. Many, however, are consider- 
ably larger. Serial sections were prepared from four 
specimens for routine examination, and it appears that 
these seed-like structures are really sporangia similar to 
those characteristic of the extinct arborescent lycopods, 
particularly the so-called Lepidocarpon alliance. 
The best preserved of the seed-bearing Lepidodendrids 
constitute the genus Lepidocarpon, which has been 
known for nearly a century, although for a long time its 
true relationship was not understood. In all of the species 
attributed to this group, the megaspore, which produces 
its gametophyte endosporally, is retained within integu- 
mentary tissues formed from the sporophyll. Even when 
[ 85 ] 
