remains and of the quantity of material necessary for an 
adequate description. From the very beginning of a 
problem the investigator is faced by the fragmentary 
nature of the plant parts and the painstaking “piecing 
together” of small fragments. Even though one can 
scarcely doubt the attachment of a particular seed to a 
twig or a given leaf to a stem, organic connection, that 
is actual union of parts, must be observed before attach¬ 
ment is proven. As a result of this necessity for caution, 
numerous generic and specific names must be applied to 
parts of a single biological species. If an investigation 
be made of hundreds of examples of the same kind, the 
fragments which show attachments, such as small branch¬ 
es on larger portions of the axis, inflorescences borne up¬ 
on twigs, and the like, may ultimately yield noteworthy 
results. However, much restraint and caution must be 
used in these problems. 
We have found, accidentally, a method which has 
revealed a surprising number of cases of organic union 
of parts: sporangia on fern fronds, spores in sporangia, 
ovules within inflorescences, fronds attached to petioles, 
and pollen-grains in staminate strobili. By the same 
method we have observed impressions of various fossil 
plants in the coal balls as well as the mineralized portions 
showing histological detail. Thus the Iowa coal ball flora 
contains nearly a dozen species known both externally 
and internally. 
Within recent years some progress has been made in 
this direction upon Mesozoic floras by Harris, Thomas, 
and Florin, but little upon Paleozoic, though Florin, 
Walton, Hartung, and the writer have made small be¬ 
ginnings. 
Method of Study 
Each coal ball was split into smaller fragments with 
a sledge-hammer. It was found that each coal ball, with 
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