selves. This pad of tissue has four club-shaped masses of 
cells of unknown significance. Presumably from one of 
these, perhaps from all, megaspores could be developed. 
I assume that this may be homologous with an archespo- 
rial pad. The gametophyte is extensive, nearly filling the 
whole cavity. 
Iowa: Dallas County, Waukee, Shuler Mine. F.O.Thompson Coll. 
: Polk County, Walnut Township, Urbandale Mine. F.O. 
Thompson Coll. 
: Lueas County, Williamson Mines 3 and 5. F.O.Thompson 
Coll. 
Kansas: Crawford County, Frontenac. F.O.Thompson and W.C. 
Darrah Coll. 
CarBoNIFEROUS: Pennsylvanian: Des Moines Series 
Summary 
The following new observations are believed to offer 
significant information concerning the Carboniferous 
lepidodendrids: 
1. A portion of the genus Lepidocystis Lesquereux 
comprises isolated seeds of Lepidocarpon. 
2. The mature Lepidocarpon sporangium is shed from 
the strobilus. 
3. In at least one species of Lepidocarpon the sporan- 
gia are shed free from the sporophyll. 
4. Lepidocarpon glabrum Darrah is described as a new 
species, demonstrating these observations. 
The knowledge that the lepidodendrids include seed- 
like forms of remarkable diversity, some of which are 
shed completely from the parent sporophyll, modifies 
considerably our concepts relating to those Carboniferous 
pteridophytic plants which produced the homologues of 
true seeds. They agree far more closely with the gym- 
nosperm seed, than has been hitherto recognized. 
I wish to express sincere appreciation to the Milton 
Fund of Harvard University and the Marsh Fund of the 
National Academy of Sciences, for aid given toward our 
investigations of American coal balls. 
[ 99 ] 
