flora contained in Iowa coal balls. Naturally the study 
of a flora containing more than sixty species, most of 
which appear to be either undescribed or very imperfectly 
known, will require a number of years for investigation. 
It is hoped, therefore, that the description of each plant 
species, or group of related species, will be published 
when its study has been completed. The descriptions and 
illustrations of three forms in this flora are now awaiting 
publication: the fructification of a new Botryopteris , the 
embryo of a Cordaicarpus, and a new seed of the Mazo - 
carport type. 
Plant Content 
The Iowa coal ball flora differs from all other de¬ 
scribed coal ball floras in that it is essentially gymnosper- 
mous rather than pteridophytic. In order of abundance 
the plant groups represented are: Cordaitales , Pterido- 
spermae, Filicales , Sphenophyllales, Calamitales , and Lep- 
idodendrales. 
Cordaitales 
The form-genus Cordaites was originally proposed for 
strap-shaped linear leaves belonging to large arborescent 
cone-bearing gymnosperms. There are several thousands 
of fragments belonging to probably a single biological 
species or possibly to two species. Most numerous of 
these are specimens of wood of the Mesoxylon type. The 
wood is found in fragments ranging in size from small 
twigs to a stump measuring nineteen inches in diameter. 
There is a large discoid pith (the so-called Artisia struc¬ 
ture). Next in abundance are the leaves which have not 
yet been identified. Both the impression and the histolo¬ 
gical structure of these foliar organs have been observed. 
Root fragments are frequently found, but their connec¬ 
tion is only implied by association. The seeds known as 
[129] 
