the specimens are isolated from the strobili which bear 
them, they always have this combination of structures. 
Thus there is a point of distinction between these seed- 
like organs and a typical seed, that is to say, in Lepido- 
carpon the sporophyll forms an integument and is shed 
as part of the ‘‘seed.”’ 
A considerable number of species attributed to Lepido- 
carpon have been described (7, 11, 18), all of which have 
been collected in rocks of Carboniferous age. They have 
proved to be of considerable abundance both in Europe 
and America. A closely related genus was described by 
Schopf (11) under the name J/liniocarpon, but the de- 
gree of difference between this form and that of Lepido- 
carpon is not great. The two best known species of Lep- 
idocarpon are L. lomaaxi Scott and L. wildianum Scott. 
The strobili of both of these resemble closely the usual 
Lepidostrobus type, but each megasporangium contains 
only one mature megaspore. Some of the species also con- 
tain three abortive spores. The sporophyll or ‘‘bract’’ 
forms an integument around the megasporangium, but a 
micropylar slit remains unclosed. The sporangium has a 
heavy wall and contains a tough megaspore membrane. 
‘The seeds became detached after attaining great size and 
an advanced degree of tissue differentiation. It is inter- 
esting to observe that the seeds of Lepidocarpon lomaat 
were considered by paleobotanists for many years to be 
those of a gymnosperm (Cordaicarpon anomalum Wil- 
liamson). Among living pteridophytes no equivalent 
structures have been observed, although in Selaginella 
the gametophyte develops within the megaspore, form- 
ing a living multicellular body, but it usually thrusts 
through the triradiate crest in the spore wall. No intimate 
relationship between the spore and the sporangium ex- 
ists. On the other hand, among many extinct lycopods 
thesporangium produces one functional megaspore which 
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